Powered surgical handpiece with removable control switch

ABSTRACT

A surgical tool system ( 30 ) with a powered surgical handpiece ( 32 ). A removable handswitch ( 39 ) is attached to the handpiece. The handswitch includes a slip ring ( 192 ) that removably holds the handswitch to the handpiece. A lever arm ( 212 ) is pivotally attached to the slip ring. A magnet ( 190 ) is fitted in the lever arm. The angle of the lever arm is set by the surgeon to indicate the on/off state and operating speed of the handpiece. Internal to the handpiece is a sensor ( 94 ) that generates a signal based on the relative proximity of the magnet. The sensor signal is thus employed as the control signal for regulating the operation of the handpiece. Thus a surgeon can selectively use the handpiece with or without the mounted control switch.

RELATIONSHIP TO EARLIER FILED APPLICATIONS

[0001] This application is a divisional of U.S. patent application Ser.No. 09/474,982, filed Dec. 29, 2000, now, U.S. Pat. No. ______, which isa divisional of U.S. patent application Ser. No. 08/689,866, filed Aug.15, 1996 now U.S. Pat. No. 6,017,354.

FIELD OF THE INVENTION

[0002] This invention relates generally to powered surgical tools and,more particularly, to a powered surgical tool with a removable controlswitch.

BACKGROUND OF THE INVENTION

[0003] In modern surgery, powered surgical tools are some of the mostimportant instruments medical personnel have available to them forperforming certain surgical procedures. Many surgical tools take theform of some type of motorized handpiece to which a cutting accessorylike a drill bit, a bur or a saw blade are attached. These tools areused to selectively remove small sections of hard or soft tissue or toseparate sections of tissue. The ability to use powered surgical toolson a patient has lessened the physical strain of physicians and otherpersonnel when performing surgical procedures on a patient. Moreover,most surgical procedures can be performed more quickly and moreaccurately with powered surgical tools than with the manual equivalentsthat preceded them.

[0004] A typical powered surgical tool system, in addition to thehandpiece, includes a control console and a cable that connects thehandpiece to the console. The control console contains the electroniccircuitry that converts the available line voltage into energizationvoltage suitable for powering the motor integral with the handpiece.Typically, the control console is connected to receive a signal from thehand or foot switch used to control the tool; based on that signal, theconsole sends appropriate energization signals to the handpiece so as tocause it to operate at the desired speed.

[0005] As the use of powered surgical tools has expanded, so has thedevelopment of different kinds of powered surgical tools that performdifferent surgical tasks. For example, a femoral reamer, used in hipreplacement surgery is a relatively slow speed drill that operates atapproximately 100 RPM, yet it draws a relatively high amount of power,approximately 400 Watts. Neurosurgery requires the use of a craniotomewhich is a very high powered drill that operates at approximately 75,000RPM and that requires a medium amount of power, approximately 150 Watts.In ear, nose and throat surgery, micro drills are often employed. Atypical micro drill rotates between approximately 10,000 and 40,000 RPMand requires only a relatively small amount of power, approximately 40Watts.

[0006] As the number of different types of powered surgical tools haveexpanded, it has become necessary to provide each type of handpiece amechanism for ensuring that it receives the appropriate energizationsignals. The conventional solution to this problem has been to provideeach handpiece with its own power console. As can readily be understood,this solution is expensive in that it requires hospitals and othersurgical facilities to keep a number of different consoles available, inthe event a specific set of tools are required to perform a givensurgical procedure. Moreover, in the event a number of differentsurgical tools are required in order to perform a given surgicalprocedure, it is necessary to provide the operating suite with theindividual consoles required by the different handpieces. Having toprovide these different consoles contributes to clutter in the operatingsuite.

[0007] An attempt to resolve this issue has been to design consoles thatcan be used to supply power to different handpieces. While theseconsoles have performed satisfactorily they are not without their owndisadvantages. Many of these consoles are arranged so that the medicalpersonnel have to manually preset their internal electronics in order toensure that they be provided the desired energization signals to thetools to which they are connected. Moreover, given the inevitable humanerror factor, time also needs to be spent to ensure that once configuredfor a new tool, a console is, in fact, properly configured. Requiringmedical personnel to perform these tasks takes away from the time thepersonnel could be attending to the needs of the patient.

[0008] There have been some attempts to provide surgical tools capableof providing some configuration information to the complementary controlconsoles. These tools typically take the form of handpieces with one ortwo resistors that collectively provide one or more analog signals backto the console. The console, based on the magnitude of these analog tooltype signals, is capable of performing some basic tool configurationfunctions such as, identify the type of the tool or cutting instrumentattached thereto. While these powered tool systems have proved useful,they are of limited value in that any significant information about thetool, such as an indication of the maximum power that can be appliedthereto, or the maximum speed at which its motor can be driven must becontained within the complementary console.

[0009] In order for a console to properly configure itself for use witha particular handpiece, the console must be preloaded with this data. Ifthe console does not contain this data, the recognition data containedwithin the tool is of relatively marginal value.

[0010] Moreover, as the number of powered surgical tools has expanded,so has the number of accessory features that can be used with the tools.Some tools, for example are provided with hand switches integral withthe tool that allow the physician to control the on/off state of thetools as well as the speed of the motor internal to the tool. Stillother tool systems are provided with foot switches. This later type ofcontrol arrangement is provided for the convenience of medical personnelwho, instead of controlling tool speed with their hands, prefercontrolling tool speed with their feet. One reason some foot switch toolcontrol assemblies are preferred is that it eliminates the need have ahand switch, which is a physical object that some physicians findinterferes with their grasp of the handpiece.

[0011] Still other powered surgical tool systems are provided withintegrated light and/or water sources. The light source typicallyincludes some type of light emitting member attached to the head of thesurgical tool. The light source is provided in the event the surgeonrequires a high intensity light to be directed onto the surgical sitewhere a surgical task is being performed. The water source is typicallyconnected to an irrigation pump. A water source is typically attached toa surgical tool in situations where it is desirable that the surgicalsite be irrigated essentially simultaneously with the execution of thesurgical task.

[0012] The conventional solution to providing surgical tools with thedesired accessories has been to design individual tools their own fixedaccessories. Some tools, for example, are provided with hand switcheswhile other tools do not include these switches. Similarly, some toolsare provided with integral conduits for supplying light and/or water tothe surgical site while other tools do not include these attachments. Ina surgical facility, the choice of surgical tool can be a function ofvariables such as physician preference and the type of surgical taskbeing performed. It can be quite costly to provide a number of differenttools, each with its own set of accessory features, in order to makeappropriate accommodation for individual personal preferences andsurgical requirements.

[0013] Moreover, the tool accessories typically require their own set ofcontrol signals to regulate their operation. Often this has beenaccomplished by providing the accessories, such as the light and waterunits, with their own control consoles that are separate from thecontrol consoles used to control the application of power to theassociated handpieces. The need to provide these additional controlconsoles further contributes to both the cost of properly equipping anoperating suite and the clutter within the suite.

[0014] There have been attempts at reducing tool proliferation byproviding surgical tools with removable hand switches and removablelight and water clips. The hand switches, once removed, reduce some ofthe structural components that are bothersome to some surgeons. However,these tools are typically provided with some type of permanent holder tosecure the hand switch in place. These holders still have the potentialof interfering with the grasp of the tools to which they are attached.Moreover, these removable units must still be provided with some type ofcontrol unit. In order to maximize the utility of these removable units,as discussed above, they are often provided with their own controlconsoles. Still another disadvantage of this type of tool assemblies isthat their light-and-water units have complementary control buttons thatare depressed in order to control the actuation of these units and theirrates of operation. The inclusion of these control buttons further addsto the overall number of control buttons that are presented to thepersonnel in the surgical suite. The presentation of these buttons, whenthey are not needed thus presents surgical personnel with extraneousinformation that may detract their attention from the matters andinstrument controls on which they should be concentrating.

[0015] Moreover, recently surgical tools have been developed that havedifferent power requirements than conventional handpieces. For example,for some surgical procedures a physician may wish to use a tool thatincludes a battery pack for applying power. Sometimes, in order to avoidthe inevitable problem of the battery drainage, the surgeon may wish tosubstitute a line-powered power unit for the battery pack. Still othernew tools do not even include traditional electrically powered motors.Examples of these tools are surgical lasers and ultrasonic scalpels.These tools have their own power requirements and complementaryaccessories. In order to make these tools available to surgicalpersonnel, it has been necessary to bring an additional set of controlconsoles into the surgical suite. Having to provide this additionalequipment has further contributed to the cost and complexity ofequipping a surgical suite.

SUMMARY OF THE INVENTION

[0016] This invention relates to an improved integrated system forpowered surgical tools that facilitates the use of tools havingdifferent power and control signal requirements and that allows theindividual tools to be used with different combinations of accessoryunits.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention is pointed out with particularity in the claims.The above and further features of the invention may be better understoodby reference to the following description taken in conjunction with theaccompanying drawings in which:

[0018]FIG. 1 depicts the basic components of the integrated surgicaltool system of this invention;

[0019]FIG. 2 is a cross sectional view of one handpiece that can beemployed as part of the integrated surgical tool system;

[0020]FIG. 3 is an exploded view of the internal components of thehandpiece motor;

[0021]FIG. 4 is a bottom view illustrating how the flex circuit ishoused in a back shell of a handpiece;

[0022]FIG. 5A is a cross sectional view of a basic cable used to provideenergization signals to a handpiece and that serves as a conduit forcontrol signals exchanged between the handpiece and the control console;

[0023]FIG. 5B is a detailed cross sectional view of a single motorconductor within the cable of FIG. 5;

[0024]FIG. 6 is an exploded view illustrating how a removable handswitch is attached to a handpiece;

[0025]FIG. 7 is an exploded view of the components forming the removablehand switch;

[0026]FIG. 8 is an exploded view illustrating how a removablelight-and-water clip is attached to a handpiece;

[0027]FIG. 9 is an exploded view illustrating the components forming thelight-and-water clip of FIG. 8;

[0028]FIG. 10 is a cross sectional view of the control cable used withthe light-and-water clip of FIG. 9;

[0029]FIG. 11 is a cross sectional view of the console-end plug of thecontrol cable used of FIG. 10;

[0030]FIG. 12 is a cross sectional view illustrating how the cable ofFIG. 10 is coupled to both a handpiece and a light-and-water clip;

[0031]FIG. 12A is a cross sectional view illustrating the electricalcoupling between the cable and the light-and-water clip;

[0032]FIG. 12B is a cross sectional view illustrating the water couplingbetween the cable and light-and-water clip;

[0033]FIG. 13 is a block diagram of the data stored in the non-volatilememory within a handpiece;

[0034]FIG. 14 is a diagram of illustration how the maximum torque of themotor in the handpiece can vary as a function of the speed of thehandpiece;

[0035]FIG. 15 is a diagram representative of the data fields within theread/write memory within a handpiece;

[0036]FIG. 16 is a blue print indicating how FIGS. 16A and 16B areassembled to form a basic block diagram of the elements forming thecontrol circuit within the console of the integrated tool system;

[0037]FIG. 17 is a blue print indicating how FIGS. 17A and 17B areassembled to form a block diagram of the main components of the mainprocessor of the control circuit;

[0038]FIGS. 18A, 18B and 18C are schematic diagrams of the componentsforming the handpiece interface of the control circuit;

[0039]FIG. 19 is a block diagram illustrating how FIGS. 19A and 19B areassembled to form a block diagram display-input/output controller of thecontrol circuit;

[0040]FIG. 20 is a block diagram illustrating how FIGS. 20A and 20B areassembled to form a block diagram of the motor controller and currentsensing circuit of the control circuit;

[0041]FIG. 21 is a schematic diagram of the motor driver of the controlcircuit;

[0042]FIG. 22 is a block diagram of the memory accessed by themicroprocessor within the main controller illustrating the modules thatare selectively executed by the microprocessor during the operation ofthe system;

[0043]FIG. 23 is a flow chart of the primary processing steps executedby the microprocessor within the main controller based on theinstructions contained within the main module;

[0044]FIG. 24 is an illustration of the sign-on screen, image, presentedby the control console when the system is initialized;

[0045]FIG. 25 is a graphical illustration of how the excess currentlimit time out period for a handpiece motor varies as a function of thecurrent operating speed of the handpiece;

[0046]FIG. 26 is an illustration of the primary user time imagepresented by the control console after the system is initialized andwhen at least one handpiece is plugged into the control console;

[0047]FIG. 27 is an illustration of the cable only/no handpiececonnected image presented by the control console when there is a cablewithout a complementary handpiece attached to the control console and anindividual attempts to actuate the cable;

[0048]FIG. 28 is a flow chart of the processing steps executed by themicroprocessor within the main controller, based on the instructionscontained within the speed set module;

[0049]FIG. 29 is a flow chart of the processing steps executed by themicroprocessor within the main controller based on the instructionscontained within the current set module;

[0050]FIG. 30 is an illustration of the run time image presented by thecontrol console when a handpiece is actuated;

[0051]FIG. 31 is an illustration of the surgeon selector image presentedby the control console; and

[0052]FIG. 32 is a block diagram of a set of accessory head data fieldsthat may be present in the handpiece memory.

DETAILED DESCRIPTION

[0053]FIG. 1 depicts the basic components of the integrated surgicaltool system 30 of this invention. System 30 includes two surgical tools,referred to as handpieces 32 and 33. Each handpiece 32 and 33 containsan electrically driven motor. A cutting attachment, here a burr 34, iscoupled to handpiece 32 so as to rotate with the actuation of the motor.A saw 35 serves as the cutting attachment for handpiece 33. The powerfor energizing the motor within the handpiece 32 or 33 comes from acontrol console 36. The control console 36 selectively energizes thehandpieces 32 and 33 in response to user-entered commands and furthermonitors the operation of the handpieces. A touch screen display 37integral with control console 36 serves as the interface through whichinformation about the handpieces 32 and 33 is presented to surgicalpersonnel and through which some commands used to control the handpiecesare supplied to the control console.

[0054] The on/off operation and speed of handpiece 32 is controlled by aremovable hand switch 39 fitted around the outside of the handpiece. Acable 43 connected between handpiece 32 and control console 36 providethe conductive paths for the signals exchanged between the handpiece andthe console. These signals include both the signals generated by thehandpiece 32 in response to the state of the hand switch 39 and theenergization signals that are applied to the motor internal to thehandpiece. Handpiece 33 is not fitted with a hand switch. Instead, theon/off state and motor speed of handpiece 33 are controlled by thedepression of pedals 44 integral with a foot switch assembly 46 alsopart of system 30.

[0055] The surgical site to which handpiece 33 is applied is illuminatedand selectively irrigated by a light-and-water clip 45 that is removablyattached to the handpiece 33. The water that is discharged fromlight-arid-water clip 45 is forced through the clip by a pump 40 that isconnected to a source 41 of suitable sterile water. In FIG. 1, pump 40is depicted as being a unit that is removably mountable within controlconsole 36.

[0056] Water is supplied from pump 40 to the light-and-water clip 45through a cable 47 that extends from control console 36 and that furtherincludes the conductors over which the signals needed to control thehandpiece 33 and the light integral with clip 45 travel. The actuationof the light and the discharge of water through the clip 45 are bothregulated by control console 36 based on commands entered through thefoot switch assembly 46.

[0057] When the system 30 determines that a handpiece 32 or 33 has beenplugged into the system, control console 36 reads data stored in memoryunits internal to the handpiece. Based on the retrieved data, thecontrol console 36 configures itself so that it can supply theappropriate energization signals to handpiece 32 or 33. As part of theinitialization process, the control console presents a set ofinstructions on the display 37 that direct the medical personnel toprovide information about any accessories that may be used inconjunction with the handpieces 32 and 33. Once the requisiteinstructions are received, the control console then regulates theoperation of the handpieces 32 and 33 based on the state of the handswitch 39, the pedals 44 and commands entered through the display 37.

[0058]FIGS. 2 and 3 depict the basic structure of a handpiece, herehandpiece 32, that is part of the system 30 of this invention. Handpiece32 includes a cylindrical motor housing 50 in which a motor 52 ishoused. Motor housing 50 is formed to have an open rear end 54 throughwhich the components forming motor 52 are inserted in the housing. Motorhousing 50 is further formed to define a neck 56 at the front end of thehousing that has a reduced diameter relative to the main body of thehousing. In the depicted version of the invention motor 52 is abrushless, Halless (sensorless) DC motor. Motor 52 includes threeseparate windings which are represented by a sleeve-like field coilassembly 58. Integral with field coil assembly 58 is a lamination stack59 which is located around substantially the entire outside of the fieldcoil assembly. A rotor 60 is rotatably fitted inside the field coilassembly 54. A set of permanent magnets 62 is secured to the outside ofthe rotor 56 so as to be located in close proximity to the field coilassembly.

[0059] The motor rotor 60 extends out of the neck 56 of the motorhousing 50. A bearing assembly 64 fitted in the neck 56 around the rotor60 holds the rotor steady. A drill housing 66 is fitted around the neck56 of the motor housing 50 so as to extend around the exposed end of therotor 56. A coupling assembly 68 is located in the drill housing 60. Thecoupling assembly, which is not part of this invention, releasablysecures the burr 34 or other cutting accessory to the rotor 56 so thatthe accessory will rotate in unison with the rotor.

[0060] Two memory units 72 and 74 are fitted in the motor housing 50 ofhandpiece 32. A first memory unit, memory unit 72, is a read onlymemory. In one preferred version of the invention memory unit 72 is anon-volatile random access memory (NOVRAM), a one-time write memory,that has a 2 k byte storage capacity. NOVRAM 72 is written to during themanufacture of the handpiece 32 and the data stored therein is retrievedby control console 36 when handpiece 32 is attached to the console. Thesecond memory unit, memory unit 74, is a non-volatile, erasable randomaccess memory. In one preferred version of the invention, memory unit 74is an electronically erasable programmable read memory (EEPROM) that hasa storage capacity of 256 bits. EEPROM 74 is written to by the controlconsole 36 as a result of the use of the handpiece 32. The datacontained in EEPROM is both read by control console 36 as part of itsinitial internal configuration process and is further read whenmaintenance work is performed on the handpiece 32. In one version of theinvention, a DS2505P manufactured by Dallas Semiconductor is employed asthe NOVRAM 72 and a DS2430AP from the same source is used as the EEPROM74.

[0061] The NOVRAM 72 and EEPROM 74 are both attached to a flex circuit76 that is located in the motor housing 50. The flex circuit 76 isformed from a non-conductive material that will not breakdown whensubject to the sterilization environment to which the handpiece 32 isexposed (Saturated steam at 270° F. at 30 psi) . One suitable materialfrom which the flex circuit 76 is formed is polyamide like materialwhich is sold by the DuPont Company under the trademark Powerflex AP.Copper traces 78 formed on the flex circuit 76 form the conductive pathsboth to the memories 72 and 74 and to the other components mounted on orconnected to the flex circuit.

[0062] The flex circuit 76 is primarily fitted between the laminationstack 59 and a sleeve-like plastic back shell 82 that is fitted aroundthe field coil assembly 58. In the illustrated version of the invention,flex circuit 76 is

[0063] shaped to have a circular head section 84. As discussedhereinafter, the external electrical connections to the flex circuit 76are made through the head section 84. An elongated, generallyrectangularly shaped spine 86 extends away from the head section 84 ofthe flex circuit 76. Two aligned arms 88 extend perpendicularly awayfrom the spine 86 a short distance away from the head section 84. NOVRAM72 is attached to a first one of the arms 88 and EEPROM 74 is attachedto the second of the arms 88.

[0064] Flex circuit 76 has a rectangularly shaped main body 90 that iscentered around the end of the spine 86 and that is spaced away from thearms 88. The main body 90 of flex circuit 76 is the portion of the flexcircuit that is located between lamination stack 59 and back shell 82.Carried on the main body 90 of the flex circuit 76 are the conductivetraces 78 that provide the electrical connections to the three windingsforming field coil assembly 58. In order to facilitate the electricalconnections to the windings the end of the main body 90 distal from thehead section is formed with three arrowhead shaped cutouts 97 to whichtraces 78 extend.

[0065] Also attached to the main body 90 of the flex circuit 76 are twoadditional devices that are specific to the handpiece in which the flexcircuit is fitted. In handpiece 32, a first one of the devices is a Halleffect sensor 94. The Hall effect sensor 94 monitors the position of amagnet internal to the hand switch 39 when the hand switch used tocontrol the on/off state and speed of the motor 50. The second device isa temperature sensor 96 that monitors the internal temperature of thehandpiece 32. In the illustrated version of the invention, Hall effectsensor 94 is mounted in a cutout space 98 formed along the perimeter ofthe flex circuit main body 90 that is distal from the head section 84 ofthe flex circuit 76. Temperature sensor 96 is secured to the surface ofthe flex circuit 76 that is directed inwardly towards the field coilassembly 58. Temperature sensor 96 is further attached to the flexcircuit so as to be located immediately inside the edge of the main body90 that is furthest from the head section 84. Consequently, when theflex circuit is fitted in handpiece 32, temperature sensor 96 is locatedadjacent the forward end of the field coil assembly 58 so as to also bein relatively close proximity with the neck 56 of the motor housing 50and the bearing assembly 64 fitted therein.

[0066] In some versions of the invention, a single conductive trace 78serves as the address/data bus for both NOVRAM 72 and EEPROM 74. Inthese versions of the invention a resistor 102 may be series connectedinto the branch of the trace that extends to one of the memories. Also,it is typically necessary to provide a reference voltage to the sensors94 and 96 secured to the flex circuit 76. As will be describedhereinafter, this reference signal is supplied by the control console36. Typically, in order to minimize spiking of the reference voltage, acapacitor 104 is connected across the conductive trace 78 over which thereference voltage is carried on the flex circuit and a complementarytrace 78 that serves as an analog signal ground.

[0067] In order to ensure that the data within memories 72 and 74 isaccurately read by control console 36, flex circuit 76 is provided withan additional conductive trace 78 that functions as a dedicated digitalground conductor. This digital ground conductor is only connected to theground pins of memories 72 and 74. This conductor is separate from theanalog ground conductor to sensors 94 and 96. It is also necessary thatthe digital ground conductor and the associated signal conductor that isconnected to memories 72 and 74 be configured as a twisted pair of wiresto the maximum extent possible, both on the flex circuit 76 and in thecable 43 connected to the control console 36.

[0068] The back shell 82, now described with reference to FIGS. 3 and 4,has a main body 106 with an open front end 108 to facilitate the fittingof the motor 52 and assembled flex circuit 76 in the shell. The mainbody 106 of the back shell is further formed to have outwardlyprojecting, longitudinally extending ribs 110. The ribs 110 provide acompression fit between the back shell 82 and the adjacent inside wallof the motor housing 50. In some versions of the invention ribs 110 areat least partially sheared off when the back shell 82 is fitted in themotor housing 50. Integral with the main body 106 of the back shell 82is an end cap 112. End cap 112 is formed with a bore 113 coaxiallyaligned with the main body 106 through which the rear portion of therotor 60 of the motor 50 extends.

[0069] Back shell 82 is further formed with an elongated, slot-likeopening 114 that extends the length of the shell through both the mainbody 106 and end cap 112. Opening 114 is dimensioned to allow the flexcircuit 76 to be positioned so that the head section 84 can be spacedaway from the end of the end cap 112, the spine 86 is seated in theopening 114 and the main body 90 disposed against the inside surface ofthe main body 106 back shell. When the flex circuit 76 is so fitted inthe back shell 82, the arms 88 of the flex circuit are located aroundthe outside of the end cap 112. The ends of the arms 88 are then seatedin slots 116 formed in the end cap 112, best seen by reference to FIG.4. In the depicted version of the invention, end cap 112 is furtherformed with flat surfaces 118 that extend from opening 114 to the slots116. Flat surfaces 118 are recessed relative to the outside diameter ofthe rest of the end cap 112. Memories 72 and 74, resistor 102 andcapacitor 104 are attached to flex circuit 76 so as to be directedtowards flat surfaces 118 of the back shell 82. Thus, owing to thepositioning of the memories 72 and 74, resistor 102 and capacitor 104 inthe relatively open spaces defined by surfaces 118, once the handpiece32 is subjected to the sterilization process, the vapor introducedaround these components is able to be drawn away therefrom relativelyquickly.

[0070] Returning to FIGS. 2 and 3, it can be seen that a front shell 122covers the outer surface of the flex circuit 76 that projects forward ofthe back shell 82 and is seated in opening 114 formed in the back shell.Front shell 122 has a ring shaped head section 126 that is seated aroundthe exposed portion of the main body 90 of the flex circuit 76. A stem128 formed integrally with the head section 126 extends rearwardlytherefrom. The front shell 122 is positioned relative to the headsection so that the front shell stem 128 is seated in the opening 114 inthe back shell so as to cover the portion of the flex circuit seated inthe opening.

[0071] A rear bearing housing 128 is fitted over the end of the end cap112 of the back shell 82. Rear bearing housing 128 has a relativelylarge diameter base 130 with an outer diameter that allows it to befitted in relatively close proximity against the inside wall of themotor housing 50. The base 130 of rear bearing housing 128 is formed todefine an elongated slot 131 in which the spine 86 of the flex circuit76 is seated. The inside of the base 130 defines a void space 134 inwhich the head section 84 of the flex circuit 76 is seated. A reduceddiameter, bearing sleeve 135 extends forward from the base 130 into thebore 113 defined in the back shell end cap 112. A rear bearing assembly132 is located in bearing sleeve 135. Rear bearing assembly 132 extendsbetween the bearing sleeve 135 and the end of the motor rotor 60 forholding the rotor for stable rotation.

[0072] A one-piece, cylindrical socket holder 137 is fitted in the endof the motor housing 50 so as to cover the rear bearing housing 128 andthe exposed head section 84 of the flex circuit 76. Socket holder 137has a tube-shaped outer body 138 that is dimensioned to be compressionfitted against the inside wall of the motor housing 50. The outer body138 is formed with an outwardly projecting, circumferential flange 140located at the rear end thereof that limits forward movement of thesocket holder 137. Outer body 138 is further formed to define anelongated slot 141 that extends along the inside wall of the outer bodyto facilitate the proper coupling of the cable 43 to the socket holder137.

[0073] A head ring 142 extends forward from the outer body 138 of thesocket holder 137. Head ring 142 has a diameter less than the diameterof the outer body 138. More particularly, the head ring 142 of thesocket holder 137 has an outer diameter that allows the head ring to befitted against the inside circumferential wall of the base 130 of therear bearing housing 128 that defines space 134. An O-ring 144 locatedaround the outer body 136 of the socket holder 137 seals the inside ofthe motor housing 50. In the illustrated version of the invention,O-ring 144 is seated in an annular slot 146 defined along the forwardouter edge of the outer body 136.

[0074] Socket holder 137 further includes a solid, cylindrical socketboss 148. Socket boss 148 extends rearward from the head ring 142 of thesocket holder 137 and is inwardly spaced from the outer body 138. Socketboss 148 is formed with a center bore 150 in which a head cap screw 152is seated. The tip end of the head cap screw 152 is seated in acomplementary bore, in the center of the rear bearing housing 128. A setof conductive sockets 154 are seated in a ring of counter-tapered bores148 formed in a circular ring around the center bore 150. The socketsprovide the conductive paths from the cable 43 to the flex circuit 76.The tip ends of the sockets 154 are seated in holes 156 formed in thehead section 84 of the flex circuit 76.

[0075]FIG. 5A is a cross sectional view of the cable 43 that containsthe conductors over which signals are exchanged with a handpiece such ashandpiece 32. Cable 43 has an outer jacket 160 formed of insulatingmaterial such as silicone rubber. Immediately inside jacket 160 is abraided shield 162 formed of tinned copper. Within shield 162 are theconductors over which energization signals are applied to the handpiecemotor 50, the memories 72 and 74 are accessed and the sensors 94 and 96are monitored. In the illustrated version of the invention, wherein thehandpiece motor 50 is a three-winding, brushless, Halless (sensorless)motor, cable 43 is provided with three motor conductors 164 each ofwhich is tied through flex circuit 76 to a separate one of the windingsforming the field coil assembly 58. Six individually insulated signalconductors 166 are provided for serving as the signal path between thecontrol console 36 and the memories 72 and 74 and the sensors 94 and 96.

[0076] As seen by reference to FIG. 5B, each motor conductor 164includes a conductive core 168 formed of copper. An insulator 170 islocated immediately around the core 168. A spiral shield 172 is locatedaround the insulator 170. An insulating jacket 174 that extends aroundshield 172 serves as the outer cover for each conductor 164. Returningto FIG. 5A it can be seen that strands of polyester filler 176 providecushioning around conductors 164 and 166. The conductors 164 and 166 aswell as the strands of filler 176 are wrapped in PTFE tape 178. Jacket160 and shield 162 are fitted around the wrapped sub-assembly.

[0077]FIG. 11 depicts the male plug 177 used to connect cable 47 tocontrol console 36. Plug 177 has the same basic components as found inthe male plug used to attach cable 43 to the control console 36.Terminal pins 179 connected to conductors 164 and 166 within the cableprovide the electrical connections to complementary socket openings,(not illustrated), on the face of the control console 36. Two of theterminal pins 179 that extend into complementary socket openings in thecontrol console are shorted together. As will be discussed hereinafter,the signal that the control console 36 asserts through the shorted pins179 is used by the control console 36 to determine whether or not acable 43 or 47 is attached to a control console socket.

[0078] An insulated handpiece plug 180 (FIG. 6) provides the connectionsat the opposite end of the cable 43 between the cable and the handpiece32. Handpiece plug 180 is provided with a number of pins 181 (FIG. 12)that provide the conductive connections between the conductors 164 and166 in the cable 43 and the sockets 154 in the handpiece 32. Handpieceplug 180 is provided with a single spline 308 (seen in FIG. 9 withrespect to plug 242 of cable 47). The spline has a generallyrectangularly shaped profile that extends the length of forward portionof the head that is fitted into socket holder 137. The spline isdesigned to be fitted into the complementary slot 141 formed in thesocket holder 137 to ensure proper alignment of the pins of the cable 43with the sockets 154 in the handpiece 32.

[0079] The removable hand switch 39 attached to handpiece 32 is nowdescribed by reference to FIGS. 6 and 7. Hand switch 39 includes a slipring 184 that is removably fitted over the motor housing 50 of handpiece32. A lever arm 186 is pivotally secured to slip ring 184 so as toextend forward along the length of the handpiece 32. A torsion spring188 located between slip ring 184 and lever arm 186 biases the lever armso that it is normally pivoted away from the handpiece. A magnet 190 isfitted in lever arm 186. The position of the magnet 190 is monitored byHall effect sensor 94 so as to provide an indication of the desiredoperating speed of the motor 50 internal to the handpiece 32.

[0080] The slip ring 184 has a plastic, sleeve like main body 192 thatis designed to be releasably compression secured over the motor housing50. In order to ensure a proper fit of the hand switch, the main body192 of the slip ring 184 is shaped to have an inside diameter that isslightly less than the outside diameter of the motor housing 50. Themain body 192 of the slip ring 184 further has an elongated slot 194that extends the length of the body in order to facilitate the removableclamping action of the slip ring 184 to the handpiece.

[0081] Main body 192 of slip ring 184 is also formed with a solid tab196, (shown in phantom), that extends inward from the rear end of themain body 192 towards the center axis of the main body. Tab 196 isdimensioned to prevent the slip ring from being fitted over the frontend of a handpiece 32 or 33. The inward-directed end of tab 196 isconfigured to be seated in a complementary cut-out 185 formed in thehandpiece plug 180 of the cable 43. The seating of the slip ring tab 196in cut-out 185 formed in the handpiece plug 180 ensures that the handswitch magnet 190 is aligned with the radial line relative to the centeraxis of the handpiece along which the complementary Hall effect sensor94 is located.

[0082] Lever arm 186 is formed out of complementary upper and lowershells 198 and 200, respectively, that are ultra-sonically weldedtogether. Upper shell 198 has a tail end 202 that is located between twoparallel, spaced apart mounting tabs 204 that extend outwardly from themain body 192 of the slip ring 184. A pin 206 that extends throughaligned openings in the tabs 204 and in the tail end 202 of the leverarm upper shell 198 secures the lever arm 186 to the slip ring 184.Torsion spring 188 is fitted around pin 206. In order to prevent spring188 from compressing against pin 206, a sleeve-like mandrel 208 isfitted in the spring and the pin is rotatably fitted in the mandrel.

[0083] Magnet 190 is housed in a movable holder 212 mounted in the leverarm 186. Holder 212 has two spaced apart, longitudinally extendingparallel legs 214. A cross web 218 extends between the legs 214. Themagnet 190 is mounted in a support collar 218 that is mounted to thecross web 216. In the illustrated version of the invention, magnet 190is positioned to extend through an elongated slot 219 formed in thelower shell 200. The legs 214 of the holder 212 are mounted in grooves220 formed in the lower shell 200 of the lever arm 186. Grooves 220 havea greater length than the complementary legs 214 so as to allow thelongitudinal movement of holder 212.

[0084] The position of holder 212 is set by the manual displacement ofopposed tabs 222 that are attached to cross web 218 and that projectoutwardly from lever arm 186. Holder 212 thus allows the magnet 190 tobe positioned in a first position relative to the longitudinal axis ofthe handpiece 32 wherein the magnet is spaced from the complementaryHall effect sensor 94 and a second position wherein it is longitudinallyclosed to the sensor. Thus, the magnet is placed in the first position,a safety position, so as to prevent unintended actuation of the motor 52in the event the lever arm 186 is inadvertently depressed. Only whenmagnet 190 is in the second position, a run position, will thedepression of the lever arm 186 bring the magnet close enough to Halleffect sensor 94 so that the sensor will detect the proximity of themagnet. In the described version of system 30, the holder magnet 190 isin the safety position when it is positioned toward the rear end of thehandpiece 32.

[0085] In the illustrated version of the invention, the far ends of thelegs 214 of holder 212 are provided with outwardly curved feet 224. Thelower shell 200 is formed with notches 226 at the ends of the grooves220 in which the feet seat when the holder is placed in the safetyposition. A second pair of opposed notches 227 are formed integrallywith the grooves forward of the first pair of notches. This seating ofthe feet 224 in the notches 226 or 227 places a resistance on themovement of the holder 212 from, respectively, the safety position orthe run position. The imposition of this resistance prevents theunintended movement of the magnet 190 from the position in which it isplaced.

[0086] An extender unit 230 is retractably seated in lever arm 186. Theextender unit 230 is provided to facilitate the use of the hand switch39 by physicians with different hand sizes and/or different techniquesfor holding the handpiece 32. Extender unit 230 includes a U-shapedguide rod 232. The opposed legs of guide rod 232 are slidably fitted incomplementary openings 234 formed in the front of the upper shell 198 ofthe lever arm 186. A head piece 236 is attached to the exposed head ofguide rod 232 so as to define a finger rest surface for the surgeon toplace his/her finger. The opposed ends of the legs of the guide rod 232are bent inwardly to prevent the extender unit 230 from being totallywithdrawn from the lever arm 186.

[0087] The light-and-water clip 45 that is secured to handpiece 33 isnow initially described by reference to FIGS. 8 and 9. Light-and-waterclip 45 includes a rear shell 240 that is secured to a complementaryhandpiece plug 242 attached to one end of cable 47. A flexible siliconcarrier tube 244 extends forward from the rear shell 240. Carrier tube244 defines the conduits through which the irrigating water flows and inwhich the conductors that carry the illuminating voltage for the lightbulb are seated. The head end of the carrier tube 244 is attached to afront shell 246 that is snap-fitted to the forward end of the handpiece33. A bulb 248 is seated in the front shell 246 for illuminating thesurgical site. A rigid outlet tube 250 is attached to the front shell246 for providing a fluid conduit through which the irrigating water isdischarged onto the surgical site.

[0088] Rear shell 240 of light-and-water clip 45 includes upper andlower halves 252 and 254, respectively, that are secured together.Seated inside a cross web 256 formed in the lower half 254 of shell 240are two outwardly directed conductive pins 258. Pins 258 provide theelectrical connection to the handpiece plug 242. A rigid water inlettube 260 extends outwardly from cross web 256 to provide a conduit forthe irrigating water. As can be seen by reference to FIG. 9, the lowerhalf 254 of rear shell 240 is provided with legs 262 that extendrearward of cross web 256. Legs 262, in addition to facilitating thecoupling of clip 45 to handpiece plug 242, protect pins 258 and tube 260so as to prevent the exposed ends thereof from being inadvertently bent.

[0089] Carrier tube 244 is clamped at one end between the upper andlower halves of rear shell 240. The carrier tube 244 is formed with afirst conduit 264 in which the water inlet tube 260 is fitted. Carriertube 244 has a second conduit 266 extending the length thereof that hasa dumbbell-shaped profile. Insulated conductors 268, shown in phantom,are fitted in the opposed ends of conduit 266. Conductors 268 areconnected to pins 258 and serve as the conductive paths over which theenergization signals are applied to the bulb 248.

[0090] It is anticipated that carrier tube 244 will have a length thatwill allow the associated front shell 246 of light-and-water clip 45 tobe attached to handpiece 33 forward of the motor housing. Moreover, theflexible nature of carrier tube 244 allows the front shell 246 to berotated relative to the fixed position of the rear shell 242. Thisallows the bulb 248 and water outlet tube 250 to be selectivelypositioned by the surgeon around the circumference of the handpiece 33.

[0091] Front shell 246 of light-and-water clip 45 has a main frame 270and a complementary cover 272 that is snap-fitted over the main frame.Main frame 270 is shaped to have an approximately C-shaped clampingmember 274 that is dimensioned to be snap fitted over the handpiece 33.A head piece 276 is attached to the clamping member 274. The shell coveris snap fitted over head piece 276 so as to facilitate the securing ofthe forward end of carrier tube 244 therebetween. Head piece 276 isformed with a first bore 278 in which bulb 248 is seated. (Not shown arethe connections between bulb 248 and the conductors 268 in the carriertube.) A heat shield 280 is fitted around bulb 248 to prevent the heatgenerated by the bulb from radiating.

[0092] Outlet tube 250 is seated in a second bore 282 formed in headpiece 276. In the depicted version of the invention, outlet tube 250 hastwo opposed sections that are parallel and axially offset from eachother and an intermediate section that connects the opposed sections.The portion of tube 250 that extends rearward from head piece 276 isfitted into the conduit 264 in carrier tube 244 for receiving theirrigating water. The opposed end of outlet tube 250 projects forwardfrom front shell 246 for delivering the water to the surgical site.

[0093] In preferred versions of the invention, both the rear shell 240and front shell 246 of light-and-water clip 45 are shaped so that thethickest sections thereof extend out no further than 0.5 inches from theadjacent outside surface of the handpiece to which they are attached. Instill more preferred versions of the invention, these shells extend outno more than 0.3 inches. The front shell clamping member 274 has alength no greater than 0.6 inches. The carrier tube 244 that serves asthe conduit for the water and conductors has, for many versions of theinvention, a maximum width of 0.4 inches and a top height of 0.25inches. In more preferred versions of the invention the maximum limitsof these dimensions are 0.25 and 0.2 inches respectively. Collectively,these features ensure that the coupling of light-and-water clip 45 to ahandpiece does not significantly interfere with handling of thehandpiece.

[0094] Cable 47, through which signals are exchanged with handpiece 33and water delivered to light-and-water clip 45, is now described byreference to FIG. 10. Cable 47 has the same basic outer jacket 160,braided shield 162 and motor conductors 164 described with respect tocable 43. An irrigation tube 286 extends longitudinally down the centerof cable 47. Cable 47 is also provided with nine signal conductors 166arranged in groups of bundles of three. The cable 47 is constructed sothat the motor conductors 164 and bundles of signal conductors 166 arelocated are alternatingly and circumferentially arranged around theirrigation tube 286. Strands of polyester filler 176 are locatedadjacent irrigation tube 286 to separate the motor conductors 164 andbundles of signal conductors 166 from each other. Conductors 164, 166,filler strands 176 and irrigation tube 286 are wrapped in PTFE tape 178.

[0095]FIG. 11 illustrates a console plug 288 attached to one end ofcable 47 for connecting the cable to control console 36 and pump 40. Theplug 288 has generally a metal or plastic body designed to be fittedinto a complementary socket, (not illustrated), mounted in the face ofthe control console 36. One end of cable 47 is fitted in the opposed endof the plug 288. A solid pin holder 290 is mounted inside plug 288. Theconductive pins 179 that provide the electrical connection between thecontrol console 36 and the conductors 164 and 166 are mounted to pinholder 290 so as to extend outwardly therefrom. It should be recognizedthat plug 288, in addition to having sufficient conductive pins 179 tofacilitate required connections to the motor and devices internal to thehandpiece 33, also has additional pins to provide an energizationvoltage to the bulb 248 mounted in clip 45.

[0096] Console plug 288 is further formed with an inlet stud 292 throughwhich irrigating water from pump 40 is introduced into cable 47. Inletstud 292 extends perpendicularly away from the main axis of the plug,the axis along which pins 179 are oriented. Inlet stud 292 is formedwith a bore 293 designed to receive a complementary outlet tube 294(FIG. 1) from the pump 40. An L-shaped connector tube 296 provides thefluid communication path from inlet stud 292 to tube 286 within cable47. One end of connector tube 296 is fitted in an inwardly directedmounting stud 298 that is axially aligned with inlet stud 292. Morespecifically connector tube 296 is fitted in a bore 300 formed in stud298 so that the tube is open to the bore 293 in the inlet stud 292. Theopposed end of connector tube 296 is fitted into an extension 302 ofirrigation tube 286 that extends rearward of the end of cable 47.

[0097]FIGS. 9, 12, 12A and 12B depict the structure of handpiece plug242 of cable 47 and how the plug is connected to handpiece 33 andlight-and-water clip 45. Plug 242 includes a main body 306 formed ofplastic to which the end of cable 47 is attached. Main body 306 isformed with a solid pin holder 307 that is dimensioned to be receivedwithin the outer body 138 of the socket holder (FIG. 2) attached to theend of the handpiece. The pins 181 that provide the electricalconnections to the handpiece are mounted in pin holder 307 and extendforwardly therefrom. As seen best in FIG. 12, the main body 306 of theplug 242 is further shaped to have an outwardly directed spline 308.Spline 308 seats in complementary slot 141 to facilitate properalignment of pins 181.

[0098] Handpiece plug 242 further includes a head 310 that is attachedto the outside of the main body 306 so as to be located diametricallyopposite the spline 308. Head 310 is provided with two conductivesockets 312. Sockets 312 are positioned to receive the complementaryconductive pins 258 that extend rearwardly from the rear shell 240 ofclip 45. The signal conductors 166 in cable 47 that supply theenergization current to the bulb 248 are attached to the pins 258,(connections not shown).

[0099] The head 310 of handpiece plug 242 is further formed with aforward directed outlet bore 314 that is located between and slightlyabove sockets 312. Outlet bore 314 is dimensioned to receive the waterinlet line 260 that extends from the light-and-water clip 45. Aduck-billed seal 316 is seated in bore 314 and positioned to be openedby inlet line 260. Seal 316 thus prevents water from being dischargedfrom cable 47 when there is no light-and-water clip 45 attached andopens to allow liquid flow when the clip is in place. Water from cable47 is directed into bore 314 through an extension line 318 integral withirrigation tube 286 that extends from the end of cable 47. The extensionline 318 is coupled into a sealed chamber 320 formed in the head 310 ofthe handpiece plug 242 from which bore 314 extends. In the depictedversion of the invention, chamber 320 is dimensioned so that extensionline 318 is coupled into the chamber at a position that is closer to thelongitudinal axis of the associated handpiece than the position fromwhich bore 314 extends from the chamber.

[0100] Legs 262 that extend rearward from the light-and-water clip 45secure the clip to the head 310 of the handpiece plug 242. Each leg 262is formed with an inwardly directed foot 322. The feet 322 seat againstopposed inwardly directed steps 324 formed in the handpiece plug head310 forward of the forward face of the head. Feet 322 are pivoted awayfrom the handpiece head 310 by the manual inward compression of thesides of the lower half 254 of the rear shell of light-and-water clip45.

[0101] Returning to FIG. 1, the structure of the foot switch assembly 46is now discussed. In the depicted version of the invention, foot switchassembly 46 has five pedals 44 a, 44 b, 44 c, 44 d and 44 e. Pedals 44 aand 44 b which are opposed right and left main pedals are relativelylarge in size are spring biased so as to assume a normally fullyextended position. Pedals 44 a and 44 b carry magnets, (not illustrated)the positions of which are monitored by complementary Hall effectsensors 327 (one shown in phantom). The selective depression of pedals44 a and 44 b actuates the associated handpiece 32 or 33. Moreparticularly, in one configuration of the system, the depression ofpedal 44 a is used to cause the associated handpiece motor to rotate ina first direction while the depression of pedal 44 b is used to causethe handpiece motor to rotate in the opposite direction. Alternatively,the system 30 can be configured so that depression of one pedal 44 a or44 b causes the associated handpiece motor to rotate in a singledirection and the depression of the other pedal is used to cause themotor to engage in oscillatory rotation. A NOVRAM 329 (shown in phantom)internal to the foot switch assembly stores data about thecharacteristics of the output signals of the particular sensors 327mounted in the assembly.

[0102] Pedals 44 c, 44 d and 44 e are located above pedals 44 a and 44b. Pedals 44 c, 44 d and 44 e control the state of three bistateswitches, respectively, foot switch assembly left, center and rightswitches. In one configuration of the invention the surgeon can depresspedal 44 c if irrigation, the actuation of pump 40, is desired. Pedal 44d is depressed in order to indicate which handpiece 32 or 33 the surgeonwants as the active handpiece. Pedal 44 e is actuated by the surgeon toindicate if he/she wants the bulb 248 associated with the activehandpiece 32 or 33 to be actuated. Foot switch assembly 46 is connectedto control console 36 by a cable 328. Cable 328 contains the conductorsover which signals generated by the Hall effect sensors associated withpedals 44 a and 44 b and the signals selectively transmitted through theswitches associated with pedals 44 c, 44 d and 44 e are supplied to thecontrol console 36. Cable 328 also contains conductors connected to theNOVRAM 329 so as to enable the control console to retrieve the datastored therein.

[0103]FIG. 13 is a block diagram of the data fields contained within theNOVRAM 72 within a handpiece such as handpiece 32. NOVRAM 72 containsthree basic types of data: header data which provides basicidentification about the handpiece in which it is installed;encyclopedia data which describes the operating characteristics of thehandpiece; and custom screen data that contains instructions about anycustom images that the handpiece requires presented on display 37.

[0104] The first data presented is the header data and the first fieldis a header length field 342 that provides an indication of the portionof the memory occupied by the header data. A set of handpieceidentification fields 343, 344, and 345 follow header length field 342.Handpiece identification fields 343-345 contain such information as thename of the handpiece, for example, sagittal saw, the part number forthe handpiece, the handpiece serial number, and a code identifying themanufacturer of the handpiece. A code revision field 346 contains anindication of the version of the data in the NOVRAM 72 that is beingread. A check sum field 347 contains data useful for errordetection/error correction of the data read from the handpiece. The datacontained in fields 342-347 are the header data.

[0105] The encyclopedia data follows the header data. The first field ofencyclopedia data is a table length field 348. Table length field 348contains an indication of the size of the NOVRAM 72 in which theencyclopedia is contained. Following table length field 348 is ahandpiece definition field 350. Handpiece definition field 350 containsinformation that describes the characteristics of the handpiece. Thisinformation can include a description of: whether the handpiece is amicro duty or heavy duty handpiece; if the forward\reverse directioncontrols are convention or in reverse orientation, whether the motor isrun with or without feedback; whether the light and water accessoriescan be used with the handpiece; and the number of significant digitsthat should be presented on the image formed on display screen 37.

[0106] The next two data fields, fields 352 and 354, are device typefields that identify the characteristics of devices that are installedinto the handpiece. In one version of the invention, each field 354 and356 is a four bit field. Each one of the 16 bit combinations serves toidentify whether or not a device is present and the features of thedevice. For example, in one code scheme bit combination 0000 is used toindicate no device is present and combination 0001 is used to indicatethe signal generated by the device is a main trigger (combinationforward and reverse trigger). This code may be contained within NOVRAM72 if the device is the described Hall effect sensor 94 (FIG. 3). Inthis code scheme, combination 0100 is used to indicate that the deviceis an internal handpiece temperature sensor 96 (FIG. 3) and that thesignal generated device is representative of the temperature of thehandpiece.

[0107] The next eight fields, fields 356-370, are voltage level fieldsthat contain information about range of signals that the devicesinternal to the handpiece generate and how they control the actuation ofthe handpiece 32. Four of the fields, fields 356-362, containinformation about the signal produced by first device, hereinaftergenerically referred to as device A. Fields 364-370 contain informationabout the signal produced by the second device, hereinafter referred toas device B.

[0108] The information contained in fields 356-370 are a function of thenature of the associated devices. For example, if the devices aresensors that generate signals represented of the user-selected operatingspeed of the motor and the temperature of the device, fields 356-362 and366-370 would, respectively, contain data about the motor speed signaland the thermal state of the handpiece. Table 1 below identifies thetype of the data that is potentially present in these fields. TABLE 1Data type based on device type. Device Is Device Is Data Field SpeedSensor Temp. Sensor 356, 364 Maximum Voltage From Voltage RepresentativeSensor (Voltage Of Device Shut-Down Representative of TemperatureMaximum Speed) 358, 366 Minimum Voltage From Voltage RepresentativeSensor (Voltage of Device Warning Representative of Temperature MinimumSpeed) 360, 368 Hysterises Voltage Undefined (Voltage Above MinimumVoltage At Which Motor Is Initially Actuated)

[0109] Fields 362 and 370 contain filter value data in the event thereis a need to digital filter the signals generated by devices A and B,respectively.

[0110] It should be recognized that the foregoing description merelydescribes the data contained in fields 356-370 for just two types ofdevices. The data contained in these fields may be significantlydifferent for other types of devices. For example, one potential deviceintegral with a handpiece may be a set of buttons that the physician canselectively depress. With this type of device, the depression of aspecific set of buttons would cause a unique signal to be generated bythe handpiece 32 that the control console 36 would, in turn, recognizeas a specific command. If these buttons form an installed device, theassociated fields 356-362 or 364-370 could contain data indicating thetype of command a particular signal produced by the device represents.Two such commands for example could be commands to raise and lower themaximum speed at which the motor internal to the handpiece can operate.

[0111] Fields 372-382 contain data regarding the coefficients used toprocess the signals produced by devices in the handpiece. Fields 372-376contain data for three coefficients used to process the signal generatedby device A. Fields 376-382 contain data for three coefficients used toprocess the data used to process the signal generated by device B.

[0112] In general it is contemplated that the data produced by devices Aor B be processed using the following polynomial function:

y=ax ² +bx+c

[0113] Where: x is the digitized version of the signal produced bydevice A or B

[0114] y is the result used by the downline processing modules internalto the control console.

[0115] It is contemplated that fields 372 and 378 contain the datarepresentative of coefficient “a”; fields 374 and 380 contain the datarepresentative of coefficient “b”; and fields 376 and 382 contain thedata representative of coefficient “c”. Thus, the data in fields 372-382provides coefficients for greater than first order correction ofvariations from the normal of the signals produced by the handpiecedevices that occur due to differences in the output characteristics ofthe individual devices.

[0116] Fields 384-392 contain data used to establish the operatingspeeds of the motor 52 (FIG. 2) internal to the handpiece. Field 384contains data representative of motor stall speed, the minimum speed(revolutions per second) at which the motor 52 should operate when thesignal from the associated handpiece device A or B is at the minimumvoltage level. Field 386 contains an indication of the lowest maximumspeed that the user can establish for the motor 50. This data makes itpossible for the medical personnel to establish their own set point forthe highest maximum speed at which they want the motor to function, ifthey wish that speed to be below the established maximum speed. Field388 contains data representative of the highest speed at which the motorcan operate. Inferentially, the data stored in field 388 is alsorepresentative of the highest maximum speed set point at which the usercan program the handpiece. Field 390 contains data indicating theincremental difference in speed that the maximum speed set point of themotor can be adjusted. For example, field 390 contains data indicatingwhether the maximum speed set point can be adjusted in increments of 100RPM, 500 RPM or 1000 RPM.

[0117] Fields 391 and 392 contain data that is used if the motor can beoperated in a forward-reverse oscillatory mode. Field 391 contains anindication of the lowest speed at which the motor can be operated in theoscillatory mode. Field 392 contains data representative of the maximumspeed at which the motor can be operated at when in the oscillatorymode.

[0118] Field 394 contains data about the gear ratio of the handpiece 32.This data is used to calculate the true speed of the cutting attachmentcoupled to the handpiece. In the handpiece, handpiece 32, a cuttingattachment is directly coupled to the motor rotor 60. Therefore for thisparticular handpiece 32, field 398 would contain data indicating a 1:1ratio between the rotation of the motor and the rotation of the cuttingattachment. Field 396 contains data about the number of poles internalto the motor. Control console 36 uses this data to regulate theapplication of energization current to the individual poles.

[0119] Fields 398 and 400 contain data about the bias current that isapplied to the handpiece in order to energize the devices A and Binternal to the handpiece 32 or 33. Fields 398 and 400, respectively,contain data about the minimum and maximum bias current that is appliedto the handpiece 32 or 33.

[0120] Fields 402-404 contain data regarding the maximum current themotor should draw when in different phases of its cycle of operation.Fields 402 and 403 contain indication of the maximum current the motorshould draw during its initial start up cycle. More specifically, field402 contains data indicating the maximum current that should be drawnwhen the motor is in the reset phase of the start up cycle. Field 403contains an indication of the maximum current the motor should drawduring the enable phase of the start up cycle. Field 404 contains anindication of the maximum current at which the motor should perform anadjustment of the coefficient of a transfer function used to determinethe current the motor should draw during its run time.

[0121] Fields 406, 408 and 410 contain the coefficients used in anequation to calculate the current set point based on defined torque setpoint. These coefficients are needed, because, as explained hereinafter,the memory also includes an indication of the maximum torque the motorshould deliver for given motor speeds. While ideally the currentdrawn-to-torque generated ratio should be linear, there may be somevariation. Consequently, coefficients that are used in agreater-than-first order equation are stored within the memory so thatthe control console can perform a relatively accurate torque-to-currentconversion. In the described version of the invention, threecoefficients, enough for providing the constants for a quadraticequation, are supplied.

[0122] Fields 412, 414 and 416 contain the coefficients employed duringmotor control when the control console is engaged in current controlmode of the motor. Fields 418, 420 and 422 contain the coefficientsemployed when the control console is engaged in the speed control modeof the motor. In both modes, the control console is engaged inproportional integral differential control of the motor. That is thecontrol console modifies the feedback signals received by the motor inorder to ensure its precise operation.

[0123] Fields 428-434 contain data representative of the torque/speedset points that define the safe operating range of the motor. As seen byline 436 of FIG. 14, a motor has a linear speed-to-torque ratio whereinthere is an inverted linear relationship between the maximum speed atwhich a motor can be driven and the torque the motor should be allowedto develop at that speed in an open loop drive mode. If, for a givenspeed the motor develops excess torque, the energization current appliedto the motor may cause undesirable results to occur such as ranging fromthe excessive heating of the motor to the wearing out of the componentsforming the motor.

[0124] In the integrated tool system 30 of this invention, fields428-434 contain set point data that allow the control console tointernally map a custom speed/torque plot 438 for the motor internal tothe handpiece 32. Fields 428, 430 and 432 each contain data indicatingfor a given percent of the maximum speed of the motor an indication ofthe percent of the maximum torque the motor should be allowed todevelop. For example, field 432 may contain an indication that when themotor is operating at 20% of its maximum speed it should develop morethan 65% of the maximum permissible torque. The maximum speed upon whichthese values are based is the maximum speed specified in motor maximumspeed field 388. The fourth speed/torque field, field 434, contains anindication of the maximum torque, the zero speed torque, the motor candevelop. The three other torque set points are based on the maximumtorque specified in field 434.

[0125] Line segments 439A to 439D of plot 438 depict the profile of thespeed-to-torque relation generated as a result of the plotting of theset point data in fields 428-434. Line segment 439A extends from thefrom the speed/torque set point specified in the first, highest speedfield, field 428, to the maximum speed/zero torque set point. As can beseen by plot 438, in preferred versions of the invention, this firstspeed/torque set point is selected so that line segment 439A issubstantially vertical. Thus, when the motor is running at the maximumspeed, the surgeon has some ability to generate a torque with the motor,bear down at a surgical site, without having the motor speed drop off.

[0126] Line segments 439B, 439C and 439D of plot 438 are shallow slopeddiagonally. Thus, the torque-at-speed plot formed by the data isarranged so that as the torque generated by the motor increases thespeed decreases at differing rates of deceleration. The diagonal profileof these plots thus ensure that as the torque generated by the motorincreases the speed of the motor will slow at a rate which will betactually sensed by the surgeon. This gives the surgeon the opportunityto manipulate the handpiece in so as to reduce the occurrence of themotor being overdriven to the point where it stalls out. In the depictedplot 438, it can be seen that the slope of the individual line segmentsis such that at lower torque limits the maximum speed decreasesrelatively slowly and that at the maximum torque limit for the motor,represented by line segment 439D, the speed decrease is set to be quitepronounced. This later affect is intended to provide the surgeon with asensory notice that the motor is producing the maximum amount of torqueit can develop.

[0127] With regard to plot 438 it should also be recognized that the twopoints that define line segment 439D are the speed/torque set point datacontained in the last intermediate field, field 432 and the zerospeed/maximum torque point specified in field 434.

[0128] Field 442 contains data representative of the length of thereset, enable and delay pulses that are applied to the internalcomponents of the console in order to ensure the correct start up of themotor. This field may also contain data indicating the maximum rate atwhich the motor should be allowed to accelerate. Field 444 contains datarepresentative of the frequency with which the braking signals should beapplied to the motor, the period in which the braking signals should beapplied to the motor and the braking signals that need to be applied tothe motor in order to ensure its complete stopping. Field 444 may alsocontain data indicating the maximum rate at which the motor can bedecelerated. The data in fields 442 and 444, in addition to controllingthe starting and stopping of the motor are also useful in controllingits actuation when the motor is being driven in the oscillatory mode.

[0129] Field 446 contains data used to control the filtering of thecurrent signal. Data used to control the filtering of the tachometersignal is contained in field 448. A field 449 contains what is referredto as time out data. The time out data contained in field 449 is used bythe control console 36 to regulate the negation of the energizationsignals to the motor in the event the motor draws a current greater thanthe current the motor should be drawing at any given instant. Field 450contains resistor compensation data. The data in field 450 is used toestablish the impedance of the speed feedback loop internal to thecontrol console 36.

[0130] Field 451 contains a warm run definition for the handpiece. Thewarm run definition represents an internal handpiece temperature atwhich the handpiece would be considered running in a warm state. Field452 contains a high current data about the handpiece. If duringoperation of the handpiece, the current draw of the handpiece exceedsthe level specified in field, the handpiece is considered to be in ahigh current draw state. As will be discussed hereinafter, the data infields 451 and 452 are used to facilitate the recordation of theoperating history of the handpiece.

[0131] Fields 453 and 454 contain data useful for controlling anyaccessory units that may be used in conjunction with the handpiece. Inone version of the invention fields 453 and 454, contain data relevantto the operating parameters of, respectively, the pump 40 and the bulb248 integral with the light-and-water clip 45. More particularly, field453 contains data indicating the maximum and minimum operating speeds ofthe pump 40 for the handpiece and the rate at which the speed of thepump can be incremented. Field 454 contains data indicating the maximumintensity of the bulb 248.

[0132] The data contained in fields 348-434 and 442-454 represent theencyclopedia data within NOVRAM 72.

[0133] Fields 458 and 460 represent the data fields that containinstructions regarding the image presented on the display 37 foroperation of the handpiece 32. Field 458 is a screen type field thatprovides an indication of whether or not the handpiece uses the standardimage or, if not, the number of custom images it requires. Field 460contains instructions for generating the custom images the handpiecerequires. Field 460 thus contains the custom screen data. It should berecognized that, in practice, field 460 is both larger in size andcontains more sub-fields than screen type field 458.

[0134] In the described version of the invention, the data containedwithin fields 342-434 and 442-460 occupy approximately 500 bytes ofmemory and NOVRAM 72 has 2 k bytes of memory. The excess memory inNOVRAM 72 makes it possible to write different versions of the data indifferent blocks within the NOVRAM. The capability of the NOVRAM 72 tohold multiple versions of the data is useful if, for example, duringmanufacture of the handpiece 32 an initial effort to write the data inthe NOVRAM fails. Moreover, during the useful life of the handpiece 32it may be desirable to provide NOVRAM 72 with new operating data. Thenew operating data may be required if, as a result of maintenancetesting it is determined that the operating characteristics of thehandpiece have changed.

[0135] The data stored in EEPROM 74 within handpiece 32 are nowdescribed by reference to FIG. 15. Field 466 is an odometer field. Inthe odometer field 466, data representative of the total time in secondand/or minutes the motor 52 integral with the handpiece 32 has beenactuated is stored. This field is updated by the control console 36during the operation of the handpiece 32. There is also a scheduledservice field 467 in which an indication of when, in terms of total timeof operation, the handpiece 32 should next be subjected to a preventivemaintenance inspection. The data in the maintenance flag field 468 isset by personnel charged with the manufacture and maintenance of thehandpiece 32.

[0136] When the handpiece 32 is attached to the control console 36, thecontrol console compares the total time the handpiece 32 has beenactuated from the odometer field 466 to the scheduled service field 467.If, as result of this comparison it appears that the handpiece 32 isapproaching a point in its run time cycle at which maintenance will soonbe required or is required, the console 36 will generate an appropriatemessage on display 37. The console 36 may also allow use of thehandpiece 32 only if the surgeon makes it a specific acknowledgementthat he/she is aware that the time period for performing maintenance onthe handpiece is past due. A service history field 468 contains anindication in past run times, of when the last three services of thehandpiece occurred.

[0137] EEPROM 74 also includes a maximum temperature field 469. Maximumtemperature field 469 contains an indication of the maximum internaltemperature of the handpiece 32 as monitored by temperature sensor 96during the operation of the handpiece. When the control console 36initializes the system 30 for use with the handpiece 32, the consoleretrieves the temperature data stored in the warm run field 454. If,during the use of the handpiece 32, the temperature of the handpieceexceeds the past highest temperature, control console 36 writes the newtemperature into field 469. The data in the maximum temperature field469 is then read from EEPROM 74 during the maintenance of the handpiece32 in order to assist in the evaluation of whether or not the handpieceis operating within acceptable parameters.

[0138] EEPROM 74 also contains warm run time field 470 in which anindication of the total time the handpiece is run at a temperatureexceeding that specified in the warm run definition field 451 is stored.There are also maximum current drawn and high current run time fields471 and 472, respectively. Maximum current drawn field contains anindication of the instantaneous maximum current drawn by the handpiece.High current run time field 472 is used to store an indication of thetotal time of operation for the handpiece at which it draws a currentthat exceeds that specified in high current definition field 452.

[0139] The average speed at which the handpiece is run is stored in anaverage speed field 473. The total times the handpiece is plugged into acontrol console 36 is recorded in a times coupled field 474. EEPROM 74also includes an override count field 475. Override count field 475contains an indication of the number of times a condition has arisen inwhich, in order for the handpiece to be operated, an override commandmust be entered through the control console.

[0140] The basic structure of the control circuit internal to thecontrol console 36 is now described by reference to the block diagramformed when FIGS. 16A and 16B are assembled together. A main controller492 is responsible for overall control of the system 30. The maincontroller 492 is the component internal to the control console 36 thatreads the data stored in the handpiece memories 72 and 74 and footswitch assembly memory 329 and that acts on the data stored in thememories. The main controller 492 receives input commands from a numberof sources such as the hand switch 39 attached to the handpiece, thefoot switch pedals 44 a, 44 b, . . . and the touch screen display 37.Based on instructions embedded in the main controller 492, the retrieveddata, the input commands and the signals from the sensors 94 and 96, themain controller 492 controls the application of energization signals tothe handpiece 32, the pump 40, the intensity of the light emitted by thebulb 248 integral with light-and-water clip 45 and the information thatis presented on the touch screen display 37.

[0141] The AC line voltage that is used by the control console 36 toboth energize the handpiece 32 and the control console is initiallyconverted into a 40 VDC signal by an AC-to-DC converter 494. In somepreferred versions of the invention, the AC-to-DC converter 494 is aplug-in module that can be physically removed from the body of thecontrol console 36. This makes it possible to provide AC-to-DCconverters 494 with different power ratings to be attached to thecontrol console 36. For example, it could be possible to provide a 200Watt AC-to-DC converter or a 400 Watt converter depending on the powerrequirements of the handpieces 32 or 33 with which the console will beused. In these versions of the invention, the AC-to-DC converter 494 isconfigured to assert a POWER_SUPPLY_SENSE (PWR_SNS) signal to the maincontroller 492. The PWR_SNS signal provides the main controller 492 withan indication of the power rating of the AC-to-DC converter 494. Thisprovides the main controller 492 with information it needs to determineif the control console 36 can supply the power required by a particularhandpiece 32 or 33 attached to the console.

[0142] A temperature sensor 495 may be fitted inside some AC-to-DCconverters 494. This sensor 495 could be located adjacent a critical,heat-generating part of the converter 495 such the converter'stransformer or power diodes. In the event the sensor 495 determines theconverter 494 is overheating, as may occur if large amounts of power aredrawn for extended periods of time, or in the event of a componentfailure, the sensor will assert a signal to the main controller 492. Insome versions of the invention, the signal asserted by temperaturesensor 495 is a specific PWR SNS signal. Also, it may be possible tosend two different signals depending on the state of the sensor 495; afirst PWR_SNS signal can be sent if the converter 494 is only startingto overheat and a second signal can be sent to indicate that theoverheating has reached a critical stage. In converters 494 that supplyrelatively low amounts of power, for example, converters that draw 200Watts or less of power, sensor 495 may not be required.

[0143] The 40 VDC is applied directly to a DC-to-DC voltage converter496. Voltage converter 496 converts the 40 VDC signal into +12 VDC, +5VDC and −5 VDC signals that are applied to other components of thecontrol console 36 as energization signals. The 40 VDC is distributedfrom voltage converter 496 to the other components of the controlconsole 36 over a 40 VDC rail 498. In order to minimize the complexityof the remaining block and schematic diagrams, only a few representativelocations where the +12 VDC, +5 VDC and −5 VDC signals are needed areillustrated. The 40 VDC is also distributed through voltage converter496 over a dedicated conductor as a MOTOR_POWER (MTR_PWR) signal whichis applied to the active handpiece 32 or 33. The MOTOR_POWER signaloriginates from the output terminal of a relay 500 internal to voltageconverter 496. The state of relay 500 is controlled by a signalgenerated by the main controller 492.

[0144] The data in the memories 72 and 74 internal to the handpieces 32and 33, as well as the output signals from the sensors 94 and 96, (thedevices), internal to the handpieces are supplied to the main controller492 from a handpiece interface 502. Handpiece interface 502 is connectedto the output terminals of the handpieces 32 and 33 through two separatehandpiece sockets 504 and 505, respectively. The signals generated bythe pedals 44 a, 44 b, . . . associated with the foot switch assembly 46are supplied to the main controller through a foot switch interface 506.

[0145] The application of the energization signals to the handpiece isregulated by a motor controller 508. Motor controller 508 is connectedto the main controller 492 so as to receive basic commands regarding thespeeds at which the motor internal to the handpieces 32 and 33 shouldrun and how the motor should be actuated. In response to receivingcommands from the main controller 492, the motor controller 508generates trigger commands to a motor driver and current sense circuit510. Motor driver and current sense circuit 510 performs two basicfunctions. First, in response to the trigger commands generated by themotor controller 508, it selectively applies the MOTOR_POWER signal tothe motor of the active handpiece 32 or 33. Secondly, the motor driverand current sense circuit 510 monitors the current applied to the motorof the handpiece 32. Signals representative of the sensed current aresupplied to both the main controller 492 and the motor controller 508.

[0146] A display input/output controller 512 both controls thepresentation of images on the touch screen display 37 and the generationof system commands based on the depression of the switch imagespresented on the display. The display input/output controller 512receives the basic commands regarding the particular image that shouldbe presented on the touch screen display 37 from the main controller492. Based on those commands, the display input/output controller 512generates the specific bit-level commands that cause the desired imageto be presented. The display input/output controller further monitorsthe touch screen display 37 to determine which of the switch imagespresented on the screen have been depressed and sends that informationto the main controller 492.

[0147] A backlight and speaker controller 514 are also connected to themain controller 492. The backlight and speaker controller 514 controlsthe intensity and contrast of a fluorescent backlight 511 associatedwith the touch screen display 37 that provides the backlighting neededto make the image presented on the display visible. The backlight andspeaker controller 514 also controls the generation of warning tones bya speaker 513. A pump controller 515 controls the application ofenergization signals to irrigation pump 40. When the pump 40 is designedas a module adapted to be fitted into control console 36, pumpcontroller 516 may be integrally attached to the module in which thepump is installed.

[0148] As seen by reference to FIGS. 17A and 17B, the main controller492 includes a microprocessor 518. In the described version of theinvention, microprocessor 518 is capable of exchanging both analog anddigital signals with the complementary components forming the controlconsole 36. One suitable microprocessor that can be employed as themicroprocessor 518 of this invention is the 80C552 manufactured byPhillips Semiconductor. Microprocessor 518 retrieves the data stored inthe memories 72 and 74 of handpieces 32 and 33 as HANDPIECE_RECOGNITION(HP_REC) signals from the handpiece interface 362. The handpieceinterface 502 also provides microprocessor 518 with the signalsgenerated by the devices A and B internal to the handpiece, HP_DVC_A andHP_DVC_B signals, respectively, and a signal representative of thecurrent drawn by the devices internal to the handpiece, an HP_CURsignal. Microprocessor 518 provides the handpiece interface with anindication of which of the two handpieces 32 connected to the controlconsole 36 should be considered the active handpiece with a digitalHP_(—)1/2 signal.

[0149] The data stored within memory 329 internal to the foot switchassembly 46 are provided to the microprocessor 518 through foot switchinterface 506 as FS_REC signals. In the described version of theinvention both the HP_REC and FS_REC signals are forwarded tomicroprocessor 518 over serial data buses. Microprocessor 518 alsoreceives from foot switch interface 46 FOOTSWITCH_FORWARD (FS_FWD) andFOOTSWITCH_REVERSE (FS_RVS) signals that are representative of thesignals generated as result of the depression of foot switch assemblypedals 44 a and 44 b, respectively.

[0150] Microprocessor 518 generates a set of signals to motor controller508 for controlling the basic production of the motor energizationsignals. The digital signals include: a MOTOR_ON\OFF (MTR_ON\OFF) signalthat provides a basic control of whether or not motor controller andcurrent sense circuit 510 is able to generate the signals used tocontrol the energization of the motor; RESET (RST) and ENABLE (ENB)signals that are cycled in order to control the initial generation ofthe energization signals; a FORWARD\REVERSE (F\R) signal that regulatesthe sequence in which the energization signals should be generated; anda BRAKE (BRK) signal that is asserted whenever the microprocessor 518determines there is a need to generate energization signals thatfacilitate the deceleration of the motor 52 in the handpiece 32.Microprocessor 518 also generates an analog SPEED_SET_POINT (SPD_SP)signal to motor controller 508 that indicates the speed at which themotor 52 internal to the handpiece 32 is to be energized. Microprocessor518 receives directly from motor controller 508 a variable frequencydigital TACHOMETER (TACH) signal that is representative of motor speed.

[0151] Microprocessor 518 also selectively forwards to motor controller508 a VCO signal, a MOTOR_VCO (MTR_VCO) signal, a DUTY signal and aMOTOR_DUTY (MTR_DTY) signal. These signals are asserted bymicroprocessor 518 when the control console 36 is used to provideenergization signals to a handpiece that is operated in a direct drivemode. A handpiece is operated in the direct drive mode when theenergization signals applied thereto are not applied directly to abrushless, Halless motor 52 such as contained within the describedhandpiece 32. For example, direct drive mode energization signals areprovided to a handpiece that is functioning as charged battery pack fora specific type of surgical tool. Alternatively, direct drive modeenergization signals are provided to handpieces wherein the actual toolis some type of motorless device such as a laser or an ultrasonic tool.

[0152] The VCO and DUTY signals are the actual signals asserted bymicroprocessor 518 to regulate the direct. drive energization of thehandpiece. These signals are multi-bit parallel signals. As discussedhereinafter, other components internal to the main controller 492convert these signals into analog formats for their use by motorcontroller 508. The MOTOR_VCO and MOTOR_DUTY signals are asserted tomotor controller 508 when the energization of the handpiece is regulatedby the VCO and DUTY signals. The MOTOR_VCO and MOTOR_DUTY signals areone-bit signals that are directly forwarded by microprocessor 518 tomotor controller 508.

[0153] Separate HANDPIECE1_ON\OFF (HP1_ON) and HANDPIECE2_ON\OFF(HP2_ON) signals are generated by the microprocessor 518 to the motordriver and current sense circuit 510. The HANDPIECEx_ON\OFF signals areused to establish to which of the handpieces 32 or 33 the energizationsignals are applied. A RESISTOR_COMPENSATION (RES_COMP) signal isgenerated by microprocessor 518 to motor controller 508 to regulate theconfiguration of the speed feedback loop internal to the motorcontroller 508.

[0154] Microprocessor 518 also generates PEAK_I_SET_POINT (PK_I_SP) andTIME_OFF (T_OFF) signals both of which are applied to the motorcontroller 508 to regulate the application of energization voltages tothe motor 52. The PEAK_I_SET_POINT signal represents at any giveninstant the maximum current the motor 52 is allowed to draw. TheTIME_OFF signal is used to establish the time out period in which theassertion of energization signals to the motor is negated after thedrawn current exceeds the limit defined by the PEAK_I_SET_POINT signal.Both the PEAK_I_SET_POINT signal and the TIME_OUT signal are generatedas multi-bit parallel signals. Other components of main controller 482convert these signals into analog format signals for assertion to motorcontroller 508.

[0155] A two-bit GAIN signal is also generated by microprocessor 518.The GAIN signal is forwarded to the motor driver and current sensecircuit 510 for establishing the gain of an amplifier that processes thesignal representative of the current drawn by the active handpiece 32 or33. The GAIN signal, as described hereinafter, is set with thePEAK_I_SET_POINT signal.

[0156] Four multi-bit parallel signals are also generated bymicroprocessor 518 to control ancillary components of the system 30.These signals are: BRIGHTNESS (BRHTNS) and CONTRAST (CNTRST) signalsthat regulate the characteristics of the image presented on display 37;a PUMP_SET_POINT signal that represents the user-selected operatingspeed for pump 40; and a SPEAKER_OUT signal representative of auser-selected volume for the speaker 513. The other components of maincontroller 492 that convert these signals into analog format will behereinafter described.

[0157] Microprocessor 518 receives from motor driver and current sensecircuit 510 an AVERAGE_I (AVG_I) signal representative of the averagecurrent drawn by the motor 52 internal to the active handpiece 32 or 33.

[0158] Data signals representative of the images to be generated on thetouch screen display 37 and of the commands entered through the displayare exchanged between microprocessor 518 and the display input/outputcontroller 512 (FIG. 19A) over a communications (COMM) bus 520. In oneversion of the invention, communications bus 520 includes two simplexserial communications lines along with an enable line over which controlsignals regulating the writing on to and reading from the communicationlines are transmitted.

[0159] The on/off state of two of the lights that form part of thesystem 30 are controlled directly by microprocessor 518. Microprocessor518 generates a LIGHT_CONTROL (LGHT_CNT) signal to regulate the on/offstate and intensity of the bulb 248 mounted to the active handpiece 32or 33 through handpiece interface 502. A CCFT_ON signal that regulatesthe on/off state of the fluorescent backlight 511 associated with thetouch screen display 37 is selectively generated by the microprocessor518 to the backlight and speaker controller 514.

[0160] Microprocessor 518 both monitors the 40 VDC signal produced byAC-to-DC converter 494 and controls the state of the relay 500 thatregulates the transmission of the 40 VDC signal as the MOTOR_POWERsignal. The 40 VDC signal is applied to microprocessor 518 over the 40VDC rail 498. Normally, microprocessor 518 asserts a MOTOR_POWER_ON(PWR_ON) signal to the relay 500 to close the relay so that the 40 VDCis applied to the motor driver and current sense circuit as theMOTOR_POWER signal. If, however, microprocessor 518 determines that the40 VDC either falls below or rises above predefined tolerance limits, itwill interpret the voltage fluctuation as a fault condition. If thisdetermination is made, microprocessor 518 negates the assertion of theMOTOR_POWER_ON signal so as to prevent the application of anyenergization signals to the handpieces 32 or 33. Microprocessor 518 willalso negate the MOTOR_POWER_ON signal if it detects any other criticalfaults within the system 30.

[0161] In the illustrated version of the invention, microprocessor 518also receives from the display input/output controller a DISPLAY_TEMP(DSPLY_TMP) signal representative of the signal of the touch screendisplay 37. The DISPLAY_TEMP signal is used by the microprocessor 518 toperform real time adjustments of the contrast of the display 37 in orderto compensate for changes in contrast that occur as a result of thefluctuations in the temperature of the display.

[0162] As shown with regard to the HP_DVC_B signal, the analog signalsreceived directly by microprocessor 518 are applied to themicroprocessor 518 through a load resistor 522. A capacitor 524 is tiedbetween the junction of the load resistor 522 and the microprocessor 518in order to filter any unusual voltage variations from the receivedsignal. Similar load resistors and filter capacitors, though notillustrated, are used to process the many, if not all, of the otheranalog signals applied to microprocessor 518.

[0163] Main controller 492 also includes a ROM-PLA 528 that is connectedto microprocessor 518. ROM-PLA 528 stores the instructionsmicroprocessor 518 retrieves in order to determine the processingfunctions it is to execute. One ROM-PLA 528 employed in control console36 is the PSD311 manufactured by WSI. ROM-PLA 528 also receives somedigital input signals from other components forming the control console36 and generates digital output signals that are processed by othercomponents forming the main controller 492. The primary data and addressexchange between microprocessor 518 and ROM-PLA is over a main processoraddress-and-data bus 530. The signals that control the reading of datafrom and writing of data to the ROM-PLA 528 are exchanged betweenmicroprocessor 518 and the ROM-PLA over a read-write control bus 532.

[0164] In the depicted version of the invention, ROM-PLA 528 receives asinputs CABLE_A (CBL_A) and CABLE_B (CBL_B) signals that indicate whetheror not a cable 43 or 47 is attached to the sockets on the face of thecontrol console 36. If a cable 43 or 47 is plugged into a socket, theshort circuit across the two tied together contact pins 179 (FIG. 11) isdetected and recognized by the main controller 492 as an indication ofan attached cable.

[0165] ROM-PLA 528 receives from the handpiece interface 502 aLIGHT_SENSE (LHT_SNS) signal. This signal indicates whether or not alight clip is attached to the active handpiece 32 and, if there is,whether or not the bulb is functioning. In the depicted version of theinvention, the LIGHT_SENSE signal is a two-bit signal. A PUMP_SENSE(PMP_SNS) signal is supplied to the ROM-PLA 528 from the pump controller515 whenever a pump 40 is connected to the system 30.

[0166] The PWR_SNS signal, depicted as a multi-bit signal, is suppliedfrom the AC-to-DC converter to the ROM-PLA 528. The PWR_SNS signal isused by the microprocessor 518 and the ROM-PLA 528 determine the amountof power the AC-to-DC converter 494 can supply. The PWR_SNS signal alsocontains an indication of temperature of the converter 494. In the eventthe PWR_SNS signal indicates that the temperature internal converter 494rises above a warning level, microprocessor 518 causes the display 37 togenerate a warning message. If the PWR_SNS signal indicates theconverter temperature rises above a critical level, microprocessor andROM-PLA 528 cease energization of the handpieces and causes a message togenerated to indicate the cause of the system 30 shutdown.

[0167] Microprocessor 518 also supplies to ROM-PLA 528 over bus 530 thePEAK_I_SET POINT, TIME_OFF, DUTY, VCO, BRIGHTNESS, CONTRAST,PUMP_SET_POINT and SPEAKER_OUT signals generated by the microprocessor.A parallel-to-serial converter internal to ROM-PLA 528 converts thesesignals into digital pulses that are outputted through a single outputline.

[0168] Status signals that indicate whether or not a particular pedal 44c, 44 d or 44 e that is part of the foot switch assembly 46 has beendepressed are supplied to the microprocessor 518 through a latch 534.The latch 534 receives from the foot switch interface 506 signalsFS_LFT, FS_CNTR and FS_RGHT indicating whether or not a particular pedal44 c, 44 d or 44 e, respectively, has been depressed. The signals aresupplied from the latch to the microprocessor 518 over the mainprocessor address-and-data bus 530.

[0169] Main controller 492 further includes a dedicateddigital-to-analog converter 536 that continually generates aSPEED_SET_POINT (SPD_SP) signal that is representative of theuser-desired speed the motor 52 internal to the active handpiece 32 or33. Digital-to-analog converter 536 is connected to the main processoraddress-and-data 530 bus for receiving a digital signal frommicroprocessor 518 upon which the SPEED_SET_POINT signal is based. Inone preferred version of the invention, the digital signal is a 12-bitsignal and the address-and-data bus 530 only has 8 data lines. In theseversions of the invention, the most significant 8 bits of the signal areinitially latched into digital-to-analog converter 536 and then theremaining 4 least significant bits are latched into the converter.

[0170] In the depicted version of the invention, digital-to-analogconverter 536 also generates an analog VREF signal which serves as areference voltage for other components internal to the control console36. The basic reference signal produced by the digital-to-analogconverter 536 initially is applied to a resistor 538. The signal is thentied to ground through two capacitors 542 and 544 in order to filter outany variations in the signal. The filtered signal is applied to thenoninverting input of an amplifier 546. The output signal from amplifier546 functions as the basic VREF signal. The VREF signal is applied asfeedback to the inverting input of amplifier 546 so that the amplifier546 functions as low impedance buffer.

[0171] The VREF signal produced by amplifier 546 is applied to thenoninverting input of amplifier 548. The output signal from amplifier548 is applied to the base of an NPN transistor 549 and the collector ofNPN transistor 550. The collector of transistor 549 is tied to the +12VDC voltage source and its emitter is tied to the base of transistor550. A VREF_FS, a reference signal that is supplied to the foot switchassembly 46, is then taken off a resistor 551 also tied to the base oftransistor 549. The VREF_FS signal is also supplied as a feedback signalto both the inverting input of amplifier 548 and the emitter oftransistor 550.

[0172] The main controller 492 thus provides a precision, low-impedanceVREF_FS signal to the foot switch assembly 46 from a source that isseparate from the source of the primary VREF signal. Amplifier 548provides overload protection for the VREF_FS signal. Thus, in the eventthere is a short in either the foot switch assembly 46 or in the cableconnecting the foot switch assembly to the control console 36, theaffects of the short are isolated from the other components of thecontrol console.

[0173] Main controller 492 further includes two combined multiplexeddigital-to-analog converters 556 and 558. Digital-to-analog converters556 and 558 are connected to the ROM-PLA 528 to receive the pulse signalrepresentations of the PEAK_I_SET_POINT, TIME_OFF, DUTY, VCO,BRIGHTNESS, CONTRAST, PUMP_SET_POINT and SPEAKER_OUT signals generatedthereby and to selectively convert these signals into their analogequivalents. The ROM-PLA 528 connection to converters 556 and 558 isover a dedicated converter bus 559. Based on the clock signals receivedin conjunction with the pulse signals, digital-to-analog converter 556converts the PEAK_SET_POINT, TIME_OFF, DUTY, VCO signals into theiranalog equivalents. Digital-to-analog converter 558 converts theBRIGHTNESS, CONTRAST, PUMP_SET_POINT, SPEAKER_OUT, and PEAK_I_SET_POINTsignals into their analog equivalents.

[0174] One conductor of converter bus 559 is a serial data conductor,not identified, that serves as the conductor over which the eightdigital pulse signals are sent from ROM-PLA 528 to both converters 556and 558. Command signals sent by ROM-PLA 528 over other conductorsforming converter bus 559 simultaneously with the pulse signals controlthe assertion of the individual signals produced by converters 556 and558.

[0175] The amplitude of the analog signals generated by converters 556and 558 are set by reference to reference signals. The VREF signalproduced by digital-to-analog converter 536 serves as the referencesignal upon which the PK_I_SP, T_OFF VCO, DUTY, PMP_SP, BRHTNS andCNTRST signals are based. The reference signal for the SPKR_OUT signalis a SPEAKER_FREQUENCY (SPKR_FREQ) signal that is produced by thedisplay input/output controller 512. Since the volume signal produced bythe analog conversion of the volume control signal is modulated by theSPKR_FREQ signal, the resultant SPKR_OUT signal is an analog audio drivesignal that is applied, after amplification, to the speaker 513 in orderto cause the generation of the desired audio tones. The main controller492 also has a reset timer 560 that functions as a failsafe resetcircuit. Reset timer 560 monitors the state of an address latch enable(ALE) signal that is transmitted from microprocessor 518 to the ROM-PLA528 over read-write control bus 532. In the event reset timer 560determines the address latch enable signal remains in one particularstate beyond a predetermined time period, the reset timer asserts aRESET_CONTROLLER (RST_CTRL) signal. The RESET_CONTROLLER signal isforwarded to microprocessor 518, ROM-PLA 528 and to the displayinput/output controller 512 to initiate the start of a control console36 reset sequence. In the depicted version of the invention, theRESET_CONTROLLER signal is forwarded to microprocessor 518 and all othercomponents that respond to this signal over a branch of the read-writecontrol bus 532.

[0176] Reset timer 560 is also tied to the rail over which the +5 VDC isdistributed. In the event the +5 VDC drops below a given value, in oneversion of the invention, +4.5 VDC, reset timer 560 will also assert theRESET_CONTROLLER signal.

[0177]FIG. 18A is a schematic diagram of the components of the handpieceinterface 502 that retrieve the data stored in the memories 72 and 74internal to the handpieces 32 and 33 and that read the signals generatedby the devices incorporated into the handpieces. A multiplexer 564connects the microprocessor 518 to the active one of the two handpieces32 connected to the control console 36. The connection established bymultiplexer 564 is determined by the state of the HP_(—)1/2 signal thatis asserted by microprocessor 518. Attached to the side of themultiplexer directed towards the handpieces 32 are two identical signalpaths over which the HP_RECx signals containing the stored data aresupplied to the microprocessor 518. Each signal path includes a pull-upresistor 566 that is tied to the +5 VDC voltage source. A surgesuppressor 568, schematically represented as a reverse biased zenerdiode, tied between resistor 566 and ground prevents excessive voltagesfrom being applied to the handpiece 32 or 33.

[0178] The circuit of FIG. 18A further includes for signal paths overwhich the signals from the four devices, (two devices associated witheach of the two handpieces 32 and 33) are applied to the input terminalsof multiplexer 564. As seen by reference to the signal path over whichthe DVC_B_(—)1 signals, the signals generated by device B of the firsthandpiece 32, travel, each signal path includes a surge suppressor 570immediately down line of the point the signal is introduced into thesignal path. A pull down resistor 572 is tied in parallel across diode570. A resistor 574 and series connected capacitor 576 are furtherconnected in parallel between the signal path and ground to furthersignal generated by the device internal to the handpiece. The signalpath further includes a current limiting resistor 578 through which thedevice signal flow into the input terminal of the multiplexer 564. Acapacitor 580 is connected between resistor 578 and multiplexer 564 thatis tied to ground provides additional filtering of the DVC_x_x signal.Multiplexer 564 produces three output signals: the HP_REC signal, theHP_DVC_A signal and the HP_DVC_B signal. The handpiece 32 or 33 fromwhich these signals are supplied is a function of the HP_(—)1/2 signal.

[0179]FIG. 18B illustrates the components of the handpiece interface 502that both supply the reference voltage to the active handpiece 32 or 33and that generate the HP_CUR signal. The V_REF signal produced by themain controller 492 is applied to the noninverting input of anoperational amplifier 582. A pull-up resistor 584 is tied between +12VDC voltage source and the output of the amplifier 582. The output ofthe amplifier 582 is applied directly to the base of an NPN transistor586. As will be described hereinafter, the output VREFx signal appliedto the actuated handpiece 32 or 33 is fed back to the inverting input ofamplifier 582 to ensure that it remains constant. The collector oftransistor 586 is tied to the +12 VDC voltage supply. The emitter oftransistor 586 is tied to an input terminal of a multiplexer 588 througha resistor 590. Multiplexer 588 controls to which of the two handpieces32 or 33 the power boosted VREFx signal is supplied. In the depictedversion of the invention, the reference signal is applied to the activehandpiece 32 or 33 across two channels in the multiplexer 588. Thisparallel routing of the reference signal is performed to minimize theeffect of the internal resistance of the multiplexer 588 on thereference signal. Two signal paths, one to each of the handpieces 32 and33, are attached to the multiplexer output ports that complement theinput terminals to which the VREF_x signal is supplied. As seen byreference to the signal path over which the VREF_(—)1 signal travels,the reference voltage to the first handpiece travels each signal pathincludes a pull down resistor 592. A surge suppressor 594 is connectedin parallel across resistor 592. The VREF_x signal is then applied tothe handpiece 32 or 33 to energize the devices internal to thehandpiece. For example, if the V_REF signal is applied to handpiece 32,the signal is used as the reference signal by both the Hall effectsensor 94 and temperature sensor 96 internal to the handpiece.

[0180] A feedback line 596 is connected between nodes 595 a and 595 bfrom which the VREF_x signal is applied to the handpiece 32 or 33 andthe inverting input of amplifier 582 so as to form a Kelvin connection.Feedback line 596 starts at the nodes 595 a or 595 b on the output sideof multiplexer 588, the side of the multiplexer closest to thehandpiece. Feedback line 596 then goes back through a third channel ofmultiplexer 588 into the inverting input of amplifier 582. When thesystem 30 is in operation, amplifier 582 monitors the difference betweenthe VREF signal from the main controller 492 and the VREF_x signalapplied to the active handpiece 32 or 33. Based on this comparison,amplifier 582 drives transistor 586 to ensure that the VREF_x signalstays constant. During this signal monitoring, owing to the highimpedance of amplifier 582, the relatively low resistance to which thefeedback signal is exposed as it flows through multiplexer 588 can beignored.

[0181] Resistor 590 functions as current sensor that monitors thecurrent drawn by the active handpiece 32 or 33 as a result of theapplication of the VREF_x signal. The signal present at the junction oftransistor 586 and resistor 590 is applied to the noninverting input ofan amplifier 598 through a resistor 600. A resistor 602 and a capacitor604 are connected in parallel between the noninverting input ofamplifier 598 to respectively, divide and filter the voltage presentedto the amplifier. The VREF_x signal, the signal present at the junctionbetween resistor 590 and multiplexer 588, is applied to the invertinginput of amplifier 598 through a resistor 606. A resistor 608 and acapacitor 610 are connected in parallel between the output of amplifier598 and the inverting input to cause the amplifier to produce a varyingaverage signal representative of the current drawn by the devicesinternal to the active handpiece.

[0182] The output signal produced by amplifier 598 is supplied to aresistor 612 wherein the signal then functions as the HP_CUR signal. Asurge suppressor 613 tied to ground clamps the HP_CUR signal to anacceptable, maximum voltage.

[0183] The output signal from amplifier 598 is also applied to reversebiased zener diode 597. The opposed end of diode 597 is tied to the baseof an NPN transistor 599. The collector of transistor 599 is tied to theoutput of amplifier 582; the emitter of the transistor is tied toground. In the event the signal produced by amplifier 598 indicates thehandpiece is drawing an excessive current, diode 597 is forced intoconduction so as to close transistor 599. The closing of transistor 599shorts the application of the VREF signal to the handpiece.

[0184]FIG. 18C is a schematic diagram of the portion of the handpieceinterface 502 that energizes and monitors the state of the bulbs 248integral with the light-and-water clips 45 that may be attached to thehandpieces 32 and 33. In the depicted system 30, the intensity of thelight illuminated by a bulb 248 is controlled by applying a pulse-widthmodulated energization signal to the bulb. Since separatelight-and-water clips 45 attached to both handpieces 32 and 33 may beprovided, handpiece interface 502 has two energization sub-circuits forselectively energizing the bulb 248 associated with each handpiece.Since the energization sub-circuits are identical, duplicate descriptionof their identical feature will hereinafter be minimized.

[0185] The bulb energization voltage is taken from the +5 VDC voltagesource through a resistor 614 that is common to both energizationsub-circuits. The energization

[0186] signal is applied to the bulb 248 as a LIGHT_1 signal through acontrol FET 616 a capable of rapidly cycling on and off. The control FET616 a is switched by the LIGHT_CONTROL signal from the microprocessor618. The LIGHT_CONTROL signal is initially applied to the base of an NPNtransistor 618 through a resistor 620. The collector of transistor 618is tied to the +5 VDC voltage source through a resistor 622. A capacitor624 is tied between the base and emitter of transistor 618.Collectively, resistor 620 and capacitor 624 dampen the slope of thepulse width modulated signal used to energize the bulb so as to minimizethe electromagnetic interface generated by this signal.

[0187] FET 616 a is a p-channel FET that is normally pulled high by the+5 VDC signal that is applied to the gate of the FET 616 a throughresistors 626 a and 627 a. The signal applied to FET 616 a thus keepsthe FET in the off, non conducting, state. The output signal at thecollector of transistor 618 is used to turn on a selected one of theFETs 616 a or 616 b. The FET 616 a or 616 b turned on by the collectoroutput signal is controlled by a multiplexer 624. The particular FET 616a or 616 b to which the multiplexer 624 applies the signal is controlledby the HP_(—)1/2 which sets the switch state of the multiplexer. Thiscollector output signal is, for example, applied to the junction ofresistors 626 a and 627 a so as to drive the voltage of the gate of FET616 a below the source voltage so as to turn on the FET. The assertionof the LIGHT_CONTROL signal by the microprocessor 518 thus causes theFET 616 a or 616 b to which the signal is applied to cyclically turn onand off. The cyclic turning on of the FET 616 a or 616 b causes theenergization voltage to be applied to the associated light-and-waterclip bulb 248.

[0188] The energization sub-circuits are further constructed to preventexcess current from being drawn by the associated light-and-water clips45 in the event there is an electrical malfunction in the clips.Resistor 614 has a relatively low resistance, typically under 10 ohms. APNP transistor 628 a is connected between resistor 614 and FET 616 a sothat base of transistor 628 a is tied to the resistor-source junctionand the collector of the transistor 628 a is tied to the gate of the FET616 a. The emitter of transistor 628 a is tied to the +5 VDC voltagesource. In the event there is a short circuit down line from FET 616 a,the voltage across resistor 614 will rise to above the turn on level fortransistor 628 a. The turning on of transistor 628 a results in theapplication of an overdrive voltage to FET 616 a which causes the FET toturn off and the application of the energization signal to thelight-and-water clip 45 to cease. This current limit circuit alsoprevents excess current from being applied to the light-and-water clipwhen the bulb 248 is initially actuated. Moreover, a surge suppressor(not illustrated), is connected between FET 616 a and ground.

[0189] The circuit of FIG. 18C also provides an indication of theclip/no-clip and good bulb/bad bulb state of the associated handpieces32 and 33. These states are determined by making an inferentialmeasurement of the resistance between the point where the signal fromthe handpiece interface 502 is applied to the light-and-water clip 45and the point where the signal is returned to ground. If there is a clip45 installed and a good bulb 248 in the clip, the resistance isapproximately one ohm. If the clip 45 has a bad bulb, the resistance isapproximately 400 ohms. If there is no clip in place or no bulb withinthe clip, there is an infinite resistance across this circuit path.

[0190] In order to measure this resistance, an intermediate resistance,approximately 400 ohms, resistors 630 a and 630 b are connected from the+5 VDC voltage source and across FETs 616 a and 616 b. When theLIGHT_CONTROL signal is not being asserted, the voltages across theseresistors are measured to provide an indication of bulb resistance,which indicates bulb state.

[0191] The measurement of the voltage across resistor 630 a or 630 b ismade by two identical comparators 632 a and 632 b that are selectivelytied to one of the resistors through multiplexer 624. Comparators 632 aand 632 b collectively produce the two-bit LIGHT_SENSE signal. Moreparticularly, the end of the selected resistor 630 a or 630 b distalfrom the +5 VDC voltage rail is applied to the inverting inputs of bothcomparators 632 a and 632 b through a resistor 634. Voltage spikes inthe signal from FET 616 a or 616 b are removed by a capacitor 638 tiedbetween the inverting inputs of comparators 632 a and 632 b and ground.The noninverting inputs of the comparators are tied to a voltage dividerwhich consists of series connected resistors 640, 642 and 644. Oneterminal of resistor 640 is tied to the +5 VDC and the other terminal istied to resistor 646. Resistor 644 is tied between resistor 642 andground. The noninverting input of comparator 632 a is tied to thejunction of resistors 640 and 642. The noninverting input of comparator632 b is tied to the junction of resistors 642 and 644.

[0192] Feedback resistors 646 a and 646 b are, respectively, tiedbetween the outputs and noninverting inputs of comparators 632 a and 632b. Pull-up resistors 648 a and 648 b are, respectively, tied between the+5 VDC source and the outputs of comparators 632 a and 632 b so that thecomparators collectively produce the two-bit LIGHT_SENSE signal. Ifthere is no light-and-water clip 45 or no bulb 248 attached to theselected handpiece 32 or 33, comparators 632 a and 632 b are presentedwith an open loop-zero voltage condition. Consequently, comparators 632a and 632 b combine to assert a first LIGHT_SENSE signal indicative of ano-clip/no-bulb state. If there is a clip 45 installed and the bulb isgood, the low resistance of the bulb causes the comparators to assert asecond LIGHT_SENSE signal indicative of clip-in/good-bulb state. Ifthere is a clip installed but the bulb is bad, the higher resistance ofthis state over the good-bulb state will cause the comparators to asserta third LIGHT_SENSE signal indicative of a clip-in/bad-bulb state.

[0193] The foot switch interface 506 contains components for the analogprocessing of the signals from the foot switch assembly 46 that aresimilar to those described with respect to FIG. 18A for the handpieceinterface 502. Resistors, capacitors and surge suppressors similar tothose used to process the DVC_x_x signals from the handpieces are usedprocess the signals that result from the depression of pedals 44 a and44 b so as to produce the FS_FWD and FS_RVS signals. Surge suppressors,filter capacitors and pull-up resistors are used to preprocess theanalog signals generated as a result of the depression of pedals 44 c,44 d and 44 e so as to respectively produce the FS_LFT, FS_CNTR andFS_RGHT signals. A circuit similar to that used to process the HP_RECxsignals is used to process the signals exchanged with the memory 329internal to the foot switch assembly 46 in order to facilitate theexchange of the FS_REC signals.

[0194] In some preferred versions of the invention, the VREF_FS signalis not applied to the foot switch assembly 46 through the foot switchinterface 506. Instead, a dedicated conductor in the control console 36is used to apply the VREF_FS directly to an appropriate socket openingon the face of the control console, conductor not illustrated.

[0195] The display input/output controller 512 is now described byreference to FIGS. 19A and 19B. Initially, it should be recognized thatthe touch screen display 37 includes both display screen 652 and atransparent touch screen 653 that is fitted over the display screen. Thedisplay screen 652 is the portion of display 37 that produces the imagesseen by the surgeon. In one embodiment of this invention, display screen652 is a liquid crystal display. A processor, integral with the displaycontrols the energization of the electrodes in the display so as tocause the desired image to appear, (processor and electrodes notillustrated). The touch screen 653 is the element of the display thatincludes the switch surfaces the surgeon selectively touches to enterinstructions and acknowledgements into the control console 36. The touchscreen 653 contains a number of transparent pressure or heat sensitiveswitches, such as variable capacitance switches, that are visuallydefined by the images presented on the display screen 652.

[0196] Display input/output controller 512 includes a display processor654. Display processor 654 performs overall control of the imagespresented on touch-screen display 37, the audio tones generated throughspeaker 513 and the generation of commands to the main controller 492based on the commands entered into the console over the touch-screendisplay. One suitable processor that can be employed as the touch screendisplay is the 80C31 processor manufactured by Phillips Semiconductor.Display processor 654 receives basic commands regarding the images to bedisplayed and audio tones to be generated from microprocessor 518 overcommunications bus 520. In response to user-entered commands enteredfrom the touch screen 653, the display processor 654 generates commandsto microprocessor 518 and forwards them to the microprocessor 518 overbus 520.

[0197] Display processor 654 also generates the SPEAKER_(—)

[0198] FREQUENCY signal that is applied to converter 558 as a speakerreference signal. The SPEAKER_FREQUENCY signal is variable frequencypulse signal. The frequency of the SPEAKER_FREQUENCY serves as the basisfor the frequency of the analog audio SPEAKER_OUT signal that isselectively asserted by converter 558. The display processor 654generates the appropriate SPEAKER_FREQUENCY signal based on specificcommand signals received from microprocessor 518. Display input/outputcontroller 512 includes a ROM-PLA 656. One suitable ROM-PLA 656 is thePSD313 marketed by Wafer Scale Integration. ROM-PLA 656 contains nonvolatile data used by the display processor 654 to control thegeneration of display images, the generation of audio tones and theassertion of commands to the main controller 492. ROM-PLA 656 alsocontains a fixed logic array that produces some of the commands thatneed to be asserted as part of the process of generating the requiredimages, tones and processor commands. Address and data signals areexchanged between display processor 654 and ROM-PLA 656 over a 16-bitaddress-and-data bus 658. The writing of data to ROM-PLA 656 and thereading of signals from the ROM-PLA is controlled by display processor654 by the exchange of signals over a separate read-write control bus660.

[0199] An EEPROM 662 is also part of the display input/output controller512. The EEPROM stores instructional data that is required by bothmicroprocessor 518 and display processor 654 and that can change duringthe use of the control console. Such data includes a list of customconfigurations a number of doctors find useful for the procedures theyperform, the last settings of the control console 36, the last contrastvoltage supply to display 37 and the last brightness setting of thedisplay. EEPROM 662 is connected to display processor 654 overaddress-and-data bus 658. The ROM-PLA 656 controls the addressing ofdata from EEPROM 662 through the generation of signals asserted over adedicated EEPROM bus 664. Microprocessor 518 receives data from andwrites data to EEPROM 662 by exchanging basic commands and data withdisplay processor 654; based on this exchange of data, display processor654 performs the required data read or write from or to the EEPROM 662.

[0200] Display input/output controller 512 has a video controller 666that actually generates the commands that cause the desired video imagesto be generated. One suitable video controller 666 is the E1330controller manufactured by Epson America. Video controller 666 generatesits specific image formation commands based on instructions receivedfrom the display processor 654 over a branch of address-and-data bus658. The reading of data by video controller 666 is controlled bydisplay processor 654 by the assertion of commands over read-write bus660. The image formation commands generated by video controller 666 aresupplied directly to the display screen 652. The processor internal tothe display screen 652, based on the received commands, causes theappropriate electrodes internal to the display screen to energize so asresult in the formation of the desired image.

[0201] A bit map memory 668 is connected directly to the video imagecontroller 666. Bit map memory 668 contains sufficient memory to storemultiple pages of data, each page representing a complete image that mayneed to be presented on the display screen 652. Bit map memory 668 isconnected directly to the video image controller 666 over a dedicatedmemory bus 670. The video image controller 666 uses the bit memory 668as a temporary storage unit for holding image formation commandsrepresentative of images that are needed for presentation on the displayscreen 652. If a particular stored image is required, the instructionsfor that image are retrieved from the bit map memory 668 by the videoimage controller 666 and forwarded by the controller 666 to the displayscreen 652.

[0202] In the described version of the system 30 of this invention,there is a temperature sensor 672 mounted to the display screen 652.Temperature sensor 672 is used to monitor the temperature of the displayscreen and assert the DISPLAY_TEMP signal which is representative of thetemperature. The DISPLAY_TEMP signal is applied to the microprocessor518. Microprocessor 518 monitors the DISPLAY_TEMP in order to make realtime adjustments of the contrast of the image presented on the displayscreen 652 in order to compensate for temperature induced changes incontrast.

[0203] The states of the switches internal to the touch screen 653 arerepeatedly evaluated by display processor 654 and ROM-PLA 656. Theswitches internal to the touch screen 653 are arranged in arow-by-column array. The ROM-PLA 656 is connected to the touch screen653 for selectively energizing a column of switches to be scanned. TheROM-PLA 656 asserts a command indicating which column is to be scannedover a dedicated column bus 674. The command asserted by the ROM-PLA 656is applied to a decoder 676. The decoder 676, in turn, energizes theselected column of switches so that the state of the individual switchestherein can be evaluated.

[0204] Once a column of switches is energized for scanning, displayprocessor 654, selectively scans each switch therein. The individualswitch scanning is performed on a row-by-row basis by the displayprocessor 654. This individual switch scanning is performed by theselective tying of each switch row to the display processor 654 over amulti-line dedicated row bus 678. The state of the signal present oneach line of the row bus 678 serves as an indication of whether or not aswitch in the selected row-and-column position is open or closed. If theswitch is closed, display processor 654 sends the appropriate message tomicroprocessor 518 over bus 520.

[0205] The display input/output controller 512 also includes a terminal680 to facilitate the connection of the control console 36 to amanufacturing/maintenance computer, (not illustrated). Themanufacturing/maintenance computer provides commands to and exchangesdata with the main controller microprocessor 518 and the displayprocessor 654 over a branch of bus 520. A gate 682 connected between bus520 and terminal 680 controls the exchange of signals with themanufacturing/maintenance computer. An enable signal that is transmittedby the display processor 654 over a conductor associated with bus 520 togate 682 controls the connection of the manufacturing/maintenancecomputer to the bus 680. The connection established by bus 520, terminal680 and gate 682 make it possible for the control console to readilyreceive software updates from the manufacturing/maintenance computer andfor the console to provide the computer with information about theoperating history of the console.

[0206] The motor controller 508, now discussed by reference to FIGS. 20Aand 20B, determines which signal connections should be made to thewindings internal to the motor 52 of the active handpiece 32 or 33 inorder to cause the desired rotation of the motor. Motor controller 508includes a motor control chip 686. Motor control chip 686 asserts therequisite command signals to the motor driver and current sense circuit510 that cause each winding to either be connected to receive theMOTOR_POWER signal or tied to ground. One suitable motor control chip686 that can be incorporated into control console 36 is the ML4426 chipmanufactured by Micro Linear.

[0207] One input signal into motor control chip 686 is theSPEED_SET_POINT signal from converter 536. Motor control chip 686 usesthe SPEED_SET_POINT signal as a reference signal for determining thespeed at which the handpiece motor 52 should rotate. In the depictedversion of the invention, the SPEED_SET_POINT signal is applied to motorcontrol chip 686 through a resistor 688. A capacitor 690 is tied betweenthe SPEED_SET_POINT input terminal and ground in order to damp anyvoltage spikes that may be in the SPEED_SET_POINT signal.

[0208] The FORWARD\REVERSE, BRAKE, RESET and ENABLE signals asserted bymicroprocessor 518 are applied to the motor control chip 686. Motorcontrol chip 686 uses the state of the FORWARD\REVERSE signal todetermine the direction in which the handpiece motor 52 should berotated. The BRAKE signal is applied to the motor control chip 686 inorder to cause the chip 686 to assert the signals to the windingsnecessary to cause a magnetic field-induced deceleration of the rotor 56of the handpiece motor 52. The RESET and ENABLE signals are applied tothe motor control chip 686 in order to start the rotation of the motor52. Based on the state of the RESET and ENABLE signals, the motorcontrol chip 686 asserts the signals that cause the initial MOTOR_POWERand ground connections to be made to the motor windings that arenecessary to accelerate the rotor 60 from the fully stopped state.

[0209] Motor control chip 686 also receives from the field coil assembly58 internal to the handpiece motor 50 three signals, W1, W2 and W3. TheW1, W2 and W3 signals are the back EMF pulse signals generated by thewindings as a consequence of the rotation of the rotor 60. Once therotor 60 starts to rotate, these back EMF signals are used by the motorcontrol chip to determine when each of the windings should be connectedto receive the MOTOR_POWER signal or tied to ground. In the depictedversion of the control console, a capacitor 689 is tied between theconductor over which the individual W1, W2 or W3 signal is applied tothe motor control chip 686 and ground for filtering the back EMF pulses.A reverse biased zener diode 691 is also connected between the conductorand ground. Diode 691 provides current protection for the motor controlchip 686 in the event the associated W1, W2 or W3 back EMF signalexceeds an acceptable potential.

[0210] The motor control chip 686 is also configured to receive as aninput signal a signal based on the PEAK_I_SET_POINT signal. Motorcontroller 508 has a comparator 692 with an inverting input to which thePEAK_I_SET_POINT signal from converter 556 is applied. ThePEAK_I_SET_POINT is applied to comparator 692 through a resistor 694. Acapacitor 696 is tied between the inverting input of comparator 692 andground in order to filter the PEAK_I SET POINT signal. A signalrepresentative of the current drawn by the windings in the handpiecemotor 52 is applied to the noninverting input of comparator 692 from themotor driver and current sense circuit 510. The output signal fromcomparator 692 is applied to the motor control chip 686. When comparator692 determines that the measured current exceeds the maximum establishedcurrent as indicated by the PEAK_I_SET_POINT signal, the output signalfrom the comparator changes state. In response to the state change ofthe output signal from comparator 692, motor control chip 686 stopsasserting LOW_SIDE_CONTROL signals. As discussed below, theseLOW_SIDE_CONTROL signals must be asserted in order to close the loopthrough which energization signals are applied to the motor windings.

[0211] The primary output signals from the motor control chip 686 areHIGH_SIDE_CONTROL (HSC) signals and LOW_SIDE_CONTROL (LSC) signals. TheHIGH_SIDE_CONTROL signals are asserted by the motor control chip 686 soas to cause the motor driver and current sense circuit 510 toselectively apply the MOTOR_POWER signal to the windings. TheLOW_SIDE_CONTROL signals are asserted so as to cause the motor driverand current sense circuit to selectively tie the windings to ground.Motor control chip 686 asserts three HIGH SIDE and LOW SIDE CONTROLsignals, one pair of signals for each winding forming the motor fieldcoil assembly 58.

[0212] The three individual HIGH_SIDE_CONTROL signals, which areasserted low, are each applied to the motor driver and current sensecircuit 510 through separate two-input OR gates 698. The MOTOR_ON signalfrom microprocessor 518 is applied to OR gates 698 as the second inputsthereto. The MOTOR ON signal is also asserted low. Thus, if the MOTOR_ONsignal is not asserted, a high signal will be present at least one inputinto each of the OR gates 698. The high signal at the input of OR gates698 will cause the gates to assert high signals which are not recognizedby the motor driver and current sense circuit 510 as control signals forapplying the MOTOR_POWER signal to the windings. The threeLOW_SIDE_CONTROL signals are applied directly to the motor driver andcurrent sense circuit 510.

[0213] Motor control chip 686 also asserts a variable frequency DC-pulseoutput signal, not identified, that is representative of the speed ofthe motor 52 sensed by the chip 686 as a consequence of the monitoringof the back EMF signals by the chip. This output signal is appliedthrough an inverter 702 to a divide-by-N counter 704. The output pulsesfrom counter 704 are applied to the microprocessor 518 as the TACHOMETERsignal.

[0214] A capacitor 706 is tied between one terminal, (not identified),of the motor control chip 686 and ground. Capacitor 706 serves as anexternal timing capacitor for establishing a “time-out period” duringwhich the LOW_SIDE_CONTROL signals are negated when the current drawn bythe handpiece motor 52 exceeds the peak current set point established bymain controller 492. Normally, a current source internal to motorcontrol chip 686 provides a charge to capacitor 706. A transistorinternal to motor control chip 686 is tied between capacitor 706 andground. This transistor is normally turned on so as to prevent capacitor706 from charging. A comparator internal to the motor controller chip686 monitors the potential across capacitor 706.

[0215] In the event the current drawn by the handpiece motor 52 exceedsthe peak current set point established by the main controller 492, motorcontrol chip 686 stops asserting the LOW_SIDE_CONTROL signals.Simultaneously, the transistor internal to the motor control chip 686that is tied across capacitor 706 is turned off. The turning off of thetransistor internal to motor control chip 686 allows capacitor 706 tocharge. The charging of capacitor 706 causes the voltage across thecapacitor to rise above an internal reference voltage within motorcontrol chip 686. Once the voltage across capacitor 706 rises above theinternal reference voltage, the output signal from the internalcomparator undergoes a state transition so as to cause the motor controlchip 686 to start reasserting LOW_SIDE_CONTROL signals. The time-outperiod for which the motor control chip 686 negates the assertion ofLOW_SIDE_CONTROL signals is a function of the time it takes capacitor706 to charge to the point where the voltage across the capacitor willrise above the internal reference voltage.

[0216] In order to provide the control console 36 with the ability tovary the time-out period in which the assertion of LOW_SIDE_CONTROLsignals are negated, a programmable current source 708 is attached tothe junction of motor control chip 686 and capacitor 706. The currentapplied to capacitor 706 by current source 708 is established by theTIME_OUT signal from converter 556.

[0217] Motor controller 508 includes a pulse width modulator controlcircuit (internal PWM), not illustrated, which is part of the speedcontrol feedback loop for controlling the duty cycle of the chop periodsas discussed hereinafter. The duty cycle of the chop period iscontrolled in order to regulate the acceleration and deceleration of therotor 56 so that the motor runs at the desired speed as indicated by theSPEED_SET_POINT signal. An external impedance network in combinationwith an amplifier integral with the internal PWM, is provided to ensurethat there is an accurate gain roll off for the handpiece motor 52attached to the control console 36 to ensure speed loop stabilitythrough the range of operation of the motor. As seen in FIGS. 20A and20B, this external network consists of a capacitor 717 and a resistor719 that are series connected between a PWM adjust terminal on motorcontrol chip 686 and ground. The external impedance network furtherincludes a resistor 720 and a capacitor 722 that are connected acrosscapacitor 717 and resistor 719.

[0218] This external impedance network of the motor controller 508 ofthis invention further includes additional components that are capableof changing the impedance of the network. In the depicted version of theinvention, the external impedance network includes a resistor 721.Resistor 721 is connected at one end to ground and is selectively tiedto the junction of capacitor 717 and resistor 719 through a multiplexer724. Multiplexer 724 connects/disconnects resistor 721 to the externalimpedance network based on the state of the RESISTOR_COMPENSATION signalasserted by the main microprocessor 518.

[0219] Motor controller 508 also controls the application of directdrive mode energization signals to a handpiece. The control console 36is operated in the direct drive mode by having the main controller 492take control of a voltage controlled oscillator (internal VCO) in motorcontroller chip 686, not illustrated, and the internal PWM. The internalVCO controls the commutation frequency of the application of theMOTOR_POWER signals to the motor windings. This commutation frequency isthe basic frequency with which the MOTOR_POWER signal is applied to theseparate windings, the time period each HIGH_SIDE_CONTROL signal isasserted. The chop cycle regulated by the internal PWM is the on-offduty cycle the winding complementary to the winding to which theMOTOR_POWER signal is applied is tied to ground. Typically multiple “on”chop periods occur during an individual commutation “on” period. Thus,during each period a particular HIGH_SIDE_CONTROL signal is asserted toone winding, the LOW_SIDE_CONTROL signal that is asserted to thecomplementary winding is cycled on and off a number of times.

[0220] In the depicted motor controller 508, the internal VCO of motorcontrol chip 686 is normally adjusted by a capacitor 710 which is tiedbetween a VCO adjust terminal on chip 686 and ground. A series connectedresistor 714 and capacitor 716 that are connected across capacitors 710and 712 also adjust the internal VCO tuning and compensation. Furtheradjustment of the internal VCO is accomplished with an additionalexternal capacitor 718 that is connected between the VCO adjust terminaland a ramp terminal also on the chip 686.

[0221] The control console 36 is operated in the direct driveenergization mode by the selective assertion of the VCO and DUTY signalsto, respectively, the internal VCO and internal PWM within the motorcontrol chip 686. The VCO and DUTY signals are applied from converter556 to inputs of separate channels of multiplexer 724. Multiplexer 724functions a switch to control the application of VCO and DUTY signals tothe motor control chip 686. The VCO signal is selectively applied frommultiplexer 724 to the VCO adjust terminal of the motor control chip686. The DUTY signal is selectively applied from multiplexer 724 to thePWM adjust terminal of the motor control chip 686. The application ofthe VCO and DUTY signals to the motor control chip is controlled by theassertion of the MOTOR_VCO and MOTOR_DUTY signals by microprocessor 518.The MOTOR_VCO and MOTOR_DUTY signals are applied to the address inputsof multiplexer 724 in order to establish the circuit connections made bythe multiplexer. Depending on the state of the MOTOR_VCO and MOTOR_DUTYsignals, none, one of or both of the VCO and DUTY signals may be appliedto the motor control chip 686. When the VCO and DUTY signals are appliedto the motor control chip 686, the chip asserts the necessary HIGH_andLOW_SIDE_CONTROL signals to effect the desired application of directdrive energization signals.

[0222] The motor driver and current sense circuit 510 is now describedby initial reference to FIG. 21. Motor driver and current sense circuit510 includes a motor driver chip 728 to which both the HIGH_andLOW_SIDE_CONTROL signals from the motor control chip 686 are applied.Based on the state of the HIGH_and LOW_SIDE_CONTROL signals, the motordriver chip 728 asserts the FET driver signals employed to cause theapplication of the MOTOR_POWER signals to the windings or to tie thewindings to ground. One suitable chip that can be used as the motordriver chip 728 is the IR2130 manufactured by International Rectifier.

[0223] In the illustrated version of the invention, motor driver chip728 is also configured to assert a FAULT signal to microprocessor 518,(connection to microprocessor 518 not shown). Motor driver chip 728asserts the FAULT signal whenever it receives HIGH and LOW_SIDE_CONTROLsignals that would cause the motor driver chip 728 to assert FET driversignals that would result in improper MOTOR_POWER or ground connects tothe windings. The FAULT signal may be asserted, for example, if themotor driver chip 728 receives an indication it is to connect onewinding to both the MOTOR_POWER signal and ground.

[0224] Motor driver and current sense circuit 510 also includes threehigh side FETs 730 each of which is series connected to a complementarylow side FET 732. Conductors 733, which supply the energization signalsto the individual windings, are connected to the source terminals ofFETs 732. Each high side FET 730 serves as the switch for connecting theconductor on which the MOTOR_POWER signal is present to one of thewindings internal to a handpiece 32 or 33. Each complementary low sideFET 732 serves as the switch to connect the handpiece winding to ground.Microprocessor 518 recognizes receipt of the FAULT signal as anindication of a fault in the application of energizaton signals to themotor and takes appropriate action.

[0225] The on\off states of FETs 730 and 732 are controlled by the FETdriver signals applied to their gates from motor driver chip 728. TheFET driver signals are applied to the gates of FETs 730 throughindividual load resistors 734. The signals present at the drains of FETs730 are applied back to the motor driver chip 728 to provide a referencefor determining the appropriate amplitude of the signals that should beprovided to the gates of the FETs 730. The signals from the drains ofthe FETs 730 are applied back to the motor driver chip 730 throughseparate resistors 736. The FET driver signals applied to the gates ofFETs 732 are applied thereto through load resistors 738. An inductor 740is connected between the drain of each FET 730 and the associated FET732-conductor 733 junction. Each inductor 740 has an inductance that isrelatively small compared to the inductance of the associated windingthat is part of the motor field coil assembly 58. For example, in someversions of the invention each inductor 740 has an inductance ofapproximately 0.1 to 10 microhenrys, in more preferred versions aninductance of 0.1 to 1 microhenrys and, in still more preferredversions, approximately 0.5 microhenrys.

[0226] Inductor 740 functions as a suppressor for a high current spikethat would otherwise develop during the commutation cycle when a FET 730is turned off and the complementary FET 732 is turned on. A currentspike occurs at this moment because, prior to the transition of thestates of the FETs, FET 730 acts as a capacitor across which there is a0 VDC potential. At the time the state of the FET 732 changes, the FET732 becomes a low resistance conductor. Consequently, the voltage acrossFET 730 rapidly charges. Owing to the low on-state resistance of FET732, this voltage causes a relatively high current spike to flow througha sense resistor 754 to ground. Inductor 740 suppresses the magnitude ofthe current spike.

[0227] Conductors 733 separate into two sets of branch conductors,conductors 742 and 744. Conductors 742 extend to the first socket on theface of the control console 36 to which handpiece 32 is connected andconductors 744 extend to the second socket to which handpiece 33 isconnected. Conductors 742 are connected to the associated socketcontacts, (not illustrated), through separate relays 746. Theopen/closed state of relays 746 is controlled by the HANDPIECE1_ON/OFFsignal. Relays 746 are configured so as to be in the open state unlessthe HANDPIECE1_ON/OFF is asserted. Conductors 744 are connected to theirassociated socket contacts through individual relays 748. Relays 748 areclosed only when the HANDPIECE2_ON/OFF signal is asserted.

[0228] Also attached to conductors 733 are three additional branchconductors 750. Conductors 750 serve as the conductors over which theW1, W2 and W3 back EMF signals from the individual windings are appliedto the motor driver chip 728.

[0229] As seen by reference to FIG. 21 the current sense portion of themotor driver and current sense circuit 510 includes a resistor 754 thatis tied between the drains of FETs 732 and ground. Resistor 754 servesas the current measuring resistor through which the current drawn by thewindings flows for measurement. The voltage across resistor 754 ismeasured as ISENSE+ and ISENSE− signals.

[0230] The ISENSE+ and ISENSE− signals are applied to the rest of themotor driver and current sense circuit which is now described byreturning to FIGS. 20A and 20B. The ISENSE+ and ISENSE− signals areapplied to a programmable amplifier 756 through resistors 758 and 760,respectively. A capacitor 761 is tied between resistors 758 and 760.Amplifier 756 amplifies the ISENSE signal by a gain of 1, 2, 5 or 10.The gain with which amplifier 756 boosts the ISENSE signal is modifiedis a function of the GAIN signal applied to the amplifier 756 frommicroprocessor 518.

[0231] The output signal from programmable amplifier 756 is applied tothe noninverting input of a fixed gain amplifier 762. A resistor 764 istied between the inverting input of amplifier 762 and ground and aresistor 766 is tied between the output of amplifier 762 and theinverting input. In one version of the invention, resistors 764 and 766are selected so that amplifier 762 has a gain of 10.

[0232] The output signal from amplifier 762 is branched to twolocations. A first location to which the output signal is branched isthe noninverting input of comparator 692 of motor controller 508. Thus,the instantaneous amplified ISENSE signal serves as the signal againstwhich the PEAK_I_SET POINT signal is compared in order to determine ifthe active handpiece 32 or 33 is drawing more than the allowed amount ofcurrent. The second location to which the output signal from amplifier762 is applied is a two-pole Butterworth filter 768. Butterworth filter768 averages the amplified ISENSE signal in order to produce theAVERAGE_I signal. The AVERAGE_I signal is applied to the microprocessor518 as the measurement of the current drawn by the active handpiece 32or 33.

[0233] Any suitable CCFT controller and audio amplifier may beincorporated into the backlight and speaker controller 514, (controllerand amplifier not illustrated). One suitable CCFT controller that can beemployed is the LT1182CS manufactured by Linear Tech. The BRIGHTNESS andCCFT ON signal from the main controller 492 are typically applieddirectly to the CCFT controller. The CONTRAST signal from the maincontroller is applied to a balancing circuit that controls theapplication of contrast signals to the display screen 652. In oneversion of the system 30, the backlight and speaker controller 514 audioamplifier amplifies the SPKR_OUT signal by a gain of approximately 5before applying the signal to the speaker 513.

[0234] The pump controller 515 includes any suitable motor controlcircuit. One such circuit is the UC 3823 controller manufactured byUnitrol. Pump controller 515 is also configured to function as aconnector that supplies the PUMP_SENSE signal to indicate whether or nota pump 40 is attached to the system 30.

[0235]FIG. 22 depicts in block diagram the primary modules stored withinROM-PLA 528 that contain the instructions that are selectively executedby microprocessor 518 during the operation of the system 30. Notdepicted is the basic operating system that performs the input/outputfunctions, handles interrupts and exceptions and performs the otheroperating chores required to make the system operate. A main module 782is the primary module. Main module 782 is the module that is firstactuated when the system 30 is initialized and the module thatselectively controls the actuation of the other modules. A NOVRAMcommunicator 784 contains the software instructions that control theretrieval of the data contained within handpiece NOVRAM 72 and thecomplementary NOVRAM within the footswitch assembly 46. An EEPROMcommunicator 786 contains the instruction used to control the reading ofdata from and the writing of data to the EEPROM 74 within the handpiece32 or 33. Communicator modules 784 and 786 are designed to retrieve andwrite data serially in accordance with the particular specifications of,respectively, the NOVRAM 72 and the EEPROM 74. Accordingly the specificdesign of the communicators 784 and 786 will not hereinafter bediscussed in any additional detail.

[0236] The ROM-PLA 528 includes three additional modules that areexecuted by microprocessor 518 so that control console 36 applies thecorrect energization signals to handpiece 32 or 33. A speed set module788 contains the instructions for generating the SPEED_SET_POINT signal.A current set module 790 contains the instructions for generating theremaining primary control signals generated by microprocessor 518, suchas the PEAK_I_SET_POINT signal. A third module, a direct drive module792, contains the instructions for generating the signals that areasserted by microprocessor 518 when the control console 36 is selectedto operate in the direct drive mode.

[0237]FIG. 23 provides a basic explanation of the process steps executedby microprocessor 518 based on the instructions contained within mainmodule 782. When control console 36 is initially actuated, a systeminitialization step 794 is initially performed. During systeminitialization step 794, microprocessor 518 as well as the othercomponents of the system, are placed in an initial ready to run state.During initialization step 794, microprocessor 518 directs the displayinput/output controller 512 to present a sign-on image 796, illustratedby FIG. 24, on display 37. Sign-on image 796 contains initialinformation that there is an interest in presenting to the system user.

[0238] After initialization step 794 is executed, microprocessor 518makes an evaluation to determine if the system 30 is to be placed in amaintenance mode as illustrated by step 798. Step 798 is actually amulti-step process. Initially, when the sign-on image 796 is presented,microprocessor reviews the data received from display input/outputcontroller 512 to determine if two phantom buttons 800 presented ontouch screen display 37 have been depressed. Buttons 800, which aredepicted in dashed lines, are not actually visible images that form partof the sign-on image 796. Instead, only support personnel, not surgicalpersonnel, know of the existence of these buttons. If the buttons 800are depressed, microprocessor 518 then evaluates whether or not amaintenance key with a maintenance code is attached to one of thesockets on the face of the console 36. A maintenance key is shapedsimilar to a handpiece motor housing 50 and plugs directly into a cablesocket 504 or 506 on control console 36. A NOVRAM is contained withinthe maintenance key. Microprocessor 518 reads the maintenance keyNOVRAM. If the microprocessor 518 determines that the NOVRAM within themaintenance key contains a valid code, the microprocessor exits the mainmodule and enters a maintenance module, represented by step 802,(maintenance module not identified).

[0239] If control console 36 is not to enter the maintenance mode,microprocessor 518 proceeds to define the system as represented by step804. In step 804, microprocessor 518 reads a number of the signals thatit is presented in order to determine how the system should beconfigured. With regard to the handpieces, microprocessor first reviewsthe state of the CABLE_x signals to determine cables 43 or 47 arecoupled to the complementary sockets 504 and 506 on the face of thecontrol console 36. If a cable 43 or 47 is connected to a socket,microprocessor 518 evaluates whether or not a handpiece 32 or 33 isconnected to the end of the cable. Initially, this evaluation begins bymicroprocessor 518 asserting or negating the HP_(—)1/2 signal as isappropriate to connect the cable, and any handpiece attached thereto, tothe microprocessor through the handpiece interface 502. In one versionof this invention, the evaluation of whether or not a handpiece isconnected to a cable is made by evaluating the state of the HP_CURsignal. If the HP_CUR signal indicates that a current is being drawn,this state is recognized as an indication that a handpiece 32 or 33 isattached to the control console 36.

[0240] If a handpiece 32 or 33 is attached to the control console 36, aspart of system definition step 804, microprocessor 518 retrieves thedata contained in the handpiece NOVRAM 72 and EEPROM 74. This dataretrieval is performed with the aid of the instructions contained in theNOVRAM communicator and EEPROM communicator modules 784 and 786,respectively. This data is forwarded to microprocessor 518 in the formof HP_REC signals.

[0241] System definition step 804 also includes a retrieval of theancillary data needed to configure the control console 36. This dataincludes determining whether or not a pump 40 and a foot switch assembly46 are connected to the control console 36. If microprocessor 518determines that a foot switch assembly 46 is present, the microprocessoraccesses the NOVRAM communicator module 784 in order to retrieve thecalibration data for the attached foot switch assembly 46 from itsmemory 329. This data is retrieved by microprocessor 518 as the FS_RECsignals. Also, the current user-selected settings for the ancillarycomponents of the system are read. These settings include, thebrightness and contrast of the display 37, the speed of the pump 40, thevolume of the speaker 513 and the intensity selection for the bulb 248attached to light-and-water clip 45. During the initial execution of thesystem definition step 804, these settings are retrieved from displayinput/output controller EEPROM 662 wherein the settings from the lastuse of control console 36 are stored.

[0242] Once system definition step 804 is complete, microprocessor 518executes an update system step 806. In update system step 806,microprocessor 518 determines the appropriate control signals based oninformation received during system definition step 804. With regard tothe ancillary components, microprocessor 518 establishes the BRIGHTNESS,CONTRAST, PUMP_SET_POINT, SPEAKER_OUT, and CCFT_ON signals. Once theappropriate levels for these control signals are determined, the signalsthat need to be asserted are asserted, while the signals that may beneeded later are stored. For example, the BRIGHTNESS and CONTRASTsignals are immediately asserted since these signals are used to controlthe presentation of all images on display 37. The PUMP_SET_POINT andLIGHT_CONTROL signals, in contrast, are stored in the event thecomponents to which these signals are applied are to be actuated.

[0243] As part of update system step 806, microprocessor 518 makes theappropriate calculations needed to run the handpieces 32 or 33 attachedto the control console 36. These calculations include the generation ofa data table representative of the speed-to-torque plot 438 of FIG. 14.This data table is based on the data retrieved from the handpiece NOVRAM74.

[0244] Microprocessor 518 also uses the data retrieved from the time outfield 449 in handpiece NOVRAM 72 to generate a data table representativeof the time out plot 808 of FIG. 25. The time out plot 808 is agraphical representation of the relationship between the measured speedof the motor 52 and the time period after the motor has drawn a currentin excess of that specified by the PEAK_I_SET_POINT for whichenergization signals should not be applied to the motor. Time out field449 contains data representative of two plot points; a first, low speedpoint and second, high speed point. As seen by reference to FIG. 25,when the motor is running at lower speeds, the time period for which itsoperation should be timed out is greater than when it is running athigher speed. As indicated by plot 808, for speeds less than the first,low speed, the time out period is the time period specified for thefirst speed. For speeds less than the second, high speed, the timeperiod is that of the second speed.

[0245] After update system step 806, microprocessor 518 performs anupdate user step 810 (FIG. 23). In update user step 810, informationregarding the status of the system 30 is presented to the user. Theprimary means by way system information is provided is the presentationof a user time image 812 on display 37, now described by reference toFIG. 26. The commands to generate the individual elements forming theimages are generated by the display input/output controller 512.Microprocessor 518, during update user step 810 and during other timesmicroprocessor displays information, actually generates general imagedisplay commands to the display input/output controller 512. Based onthese commands, display input/output controller 512 causes theappropriate image to be presented on the display 37.

[0246] User time image 812 includes a set of buttons, icons and datalines depending on the particular state of the system. Along the bottomright edge of image 812, smaller images indicate whether or not anyhandpieces are connected to the complementary sockets of the controlconsole 36. If handpieces 32 or 33 are connected to both sockets,buttons 814 and 816 appear indicating the presence of the handpieces.The user can then select one of the handpieces to be active bydepressing the button 814 or 816 for the associated socket. If neitherbutton 814 and 816 are depressed, each button has the three-dimensionalprofile of button 816 and the handpiece symbol within the button appearswhite. Once a button is depressed, it has the flat profile of button 814and the handpiece symbol within the button goes black so as tocollectively provide a quick visual indication of which of the twosockets has the active handpiece. Main module 782 further includesinstructions that cause microprocessor 518 to recognize the assertion ofthe FS_CNTR signal as an indication to switch the active handpiece fromthe designated one to the inactive one. Regardless of the means by whicha handpiece is selected, microprocessor 518 negates or asserts theHP_(—)1/2 signal as is necessary to connect the selected handpiece tothe control console 36 through handpiece interface 502.

[0247] The illustrated user time image 812 also includes an auxiliarybutton 817. Button 817 is used to indicate the presence of and controlthe active state of handpieces that could be energized by the system butthat do not include the NOVRAM with handpiece data as described withreference to handpieces 32 and 33.

[0248] In the event a cable 43 or 47 with no handpiece is attached tocontrol console 36, a cable only icon 818 appears on the screen asrepresented by cable only image 820 now described by reference to FIG.27. Alternatively, in some versions of the invention a socket cable-onlystate is represented as a button without a handpiece symbol therein. Ifa person depresses the cable only the button or foot switch 44 d,microprocessor 518 causes a large no handpiece detected icon 822 to bepresented on display 37.

[0249] Returning to FIG. 26, it can be seen that if a button 814 or 816associated with a handpiece 32 or 33 connected to control console 36 isdepressed, other information is presented as part of user time image812. If a foot switch assembly 46 is attached to control console 36, afoot switch icon 826 is presented.

[0250] If a light-and-water clip 45 is attached to the selectedhandpiece 32 or 33, and these ancillary components are compatible withthe handpiece, microprocessor 518 will cause image 812 to includebuttons 828 and 830 indicating the availability of these features. Itshould be recognized that microprocessor 518 will only cause button 828,the light option button, to be presented if the LIGHT_SENSE signal fromthe handpiece interface 502 indicates that for the active handpiece thebulb 248 in light-and-water clip 45 is in the good state. If theLIGHT_SENSE signal indicates the bulb 248 is burned out, microprocessor518 will instruct display input/output controller 512 to generate anappropriate fault message on screen 37. Depression of buttons 828 and830 will, respectively, cause bulb 248 and pump 40 to be actuated withthe actuation of the handpiece to which they are coupled.

[0251] If appropriate for the handpiece, buttons 832 and 834respectively provide an indication of whether or not the handpiece canbe driven in the forward or reverse direction. Depression of one of thebuttons 832 and 834 will cause the button to flatten and the symbolcontained therein to darken as indicated by button 834. An option button838 gives the user the opportunity of switching to different screensthat present switches that allow the user to control the ancillarycomponents of the system 30. The buttons associated with the optionscreens allow the user to control the brightness and contrast of theimages presented on the display, the volume of the speaker 513, the rateat which pump 40 supplies water and the intensity of the light emittedby the bulb associated with the light-and-water clip 45. Moreover, asdescribed hereinafter, a special options screen allows the surgicalpersonnel to enter a set of pre-defined system settings that arecustomized for a specific procedure performed by an individual doctor.

[0252] Another feature that can be selected by initial actuation ofoptions button 838 is the language in which information about the system30 is presented. In one version of the invention, at the time the useris allowed to select the settings for the display 37 and speaker 513,display input/output controller 512 also presents a set of buttons andicons that allow the user to select the language in which theinformation presented on display 37 is presented.

[0253] For some handpieces, still other option features allow the userto set the rate at which the motor internal to the handpiece acceleratesor decelerates. The fastest acceleration rate is based on data containedin NOVRAM field 442. The fastest deceleration is contained in NOVRAMdata field 444.

[0254] User time image 812 also includes a tool identification line 839that provides the name of the active handpiece 32 or 33. This name isbased on the data retrieved from handpiece identifier field in NOVRAM72. Immediately below tool identification line 839 is maximum speedidentifier 840. Maximum speed identifier 840 is a data line thatindicates the maximum speed at which the handpiece 32 or 33 can beoperated. It should be recognized that this speed, as well as all otherspeed information presented on display 37 are “tip speeds” that is,speeds at the tip end, the driving end, of the handpiece. If there is atransmission within the handpiece, microprocessor 518 will make theappropriate speed conversion based on the data contained within gearratio field 394 of NOVRAM 72 to present tip speed to the surgicalpersonnel.

[0255] Immediately to the left of maximum speed identifier 840 are speedadjustor buttons 842. Speed adjustor buttons 842 allows the medicalpersonnel to reset the maximum speed so it can be adjusted downward fromthe actual maximum speed of the handpiece. During update system step806, microprocessor 518 will selectively adjust the maximum speed of thehandpiece subject to the limit data retrieved from fields 386, 388 and390 in handpiece NOVRAM 72. A slide bar 843 is located between speedadjustor buttons 842. Slide bar 843 provides surgical personnel with avisual indication of the extent it is further possible for them toeither increase or decrease the maximum speed of the handpiece.

[0256] Also as part of user update step 810, microprocessor 518 willgenerate the appropriate signals to the display input/output controller512 to cause controller 512 to generate the appropriateSPEAKER_FREQUENCY signals so that speaker 513 will produce theappropriate audio tones. Alternatively, the display processor 654internal to display input/output controller 512 may be configured toautomatically generate the appropriate SPEAKER_FREQUENCY signals basedon the image generation commands it receives from microprocessor 518. Inone version of the invention, an audio tone is generated each time abutton or foot switch 44 is depressed in order to provide audioconfirmation that the button/switch was depressed. Microprocessor 518and display processor 654 cooperate to cause the generation of other,distinct audio tones when either new information is presented on thedisplay 37 and/or it is determined that a particular warning needs to bepresented to the system user.

[0257] Once user update step 810 is executed, microprocessor 518determines if the user has entered a command indicating use of theselected handpiece is now required, represented in FIG. 23 by motorswitch on step 844. In this step, microprocessor 518 reviews the stateof the on-off switch of the active handpiece, the appropriate HP_DVC_xsignal, and the FS_FWD and FS_RVS signals, to determine if any of thesesignals is above its hystersis level as specified by the data in thecomplementary memories. If all of these signal states are below theirhystersis, start, levels, microprocessor 518 returns and executes anabbreviated form of the system definition step 804.

[0258] In the abbreviated form of step 804, microprocessor reviews thesignals presented to it to determine if the state of any of the signalshas changed. As part of this review, microprocessor 518 reads the headerdata contained in the NOVRAMs 72 of the handpieces attached to thecontrol console 36. A comparison revealing that the header data has notchanged is interpreted as an indication that the same handpieces arestill attached to the control console 36. Changes in the header data areinterpreted as an indication that a new handpiece has been attached tothe control console 36. If this later condition exists, microprocessor518, reads the encyclopedia data for the handpiece.

[0259] As part of this abbreviated define system step, microprocessor518 also reviews what, if any, changes the user has been made to thesystem 30. Microprocessor 518 receives information regarding thesechanges in the form of data messages from the display processor 654 thatindicate which, if any, buttons presented on display 37 have beenactuated. These changes include adjustments of such variables as maximumtool speed, display brightness, and pump speed, the selection of a newhandpiece to be active, or the activation of device such as the lightbulb 248 of clip 45.

[0260] In the described version of the invention, main module 784further includes instructions that cause microprocessor 518 to recognizethe continued assertion of the FS_LEFT signal as a result of thedepression of footswitch 44 c as indication that the pump 40 is to beactuated regardless of the on/off state of the associated handpiece. Thecontinued assertion of the FS_RGHT signals as a result of the depressionof foot switch 44 e is recognized by microprocessor 518 as an indicationthat the bulb 248 is to be actuated regardless of the on/off state ofthe complementary handpiece. The short term depressions of switches 44 cand 44 e are recognized as simple commands to activate the pump andbulb, respectively, with the actuation of the handpiece.

[0261] After microprocessor 518 performs the abbreviated define systemstep 804, similar abbreviated update system and update user steps 806and 810, respectively, are executed. In the abbreviated update systemstep 806, microprocessor 518 makes the appropriate adjustments to thedata it generates that control the other components of the system 30.For example, if FS_LFT signal was received for an extended period oftime, microprocessor 518 will generate the appropriate PUMP_SET_POINTsignal so as to cause pump controller 515 to actuate the pump 40. In theupdate user step 810, microprocessor 508 generates the appropriatecommands to the display input/output controller 512 to cause theappropriate images regarding any changes in system state.

[0262] When microprocessor loops between steps 804, 806, 810 and 844, inother words no handpiece has been actuated, the system 30 is referred toas being in a user time mode.

[0263] If as a result of a review of the HP_DVC_x, FS_FWD and FS_RVSsignals during motor switch on step 844, microprocessor 518 determinesthat surgical personnel want a handpiece to be activated, system 30transitions from a user time mode to a run time mode. This transitionbegins with microprocessor 518 rereading the data in handpiece EEPROM 74as represented by step 846. The reread of EEPROM 74 is necessarybecause, as will become clear hereinafter, the data contained thereinmay have been updated after the initial read of the EEPROM.

[0264] After the handpiece EEPROM 74 has been read, microprocessor 518executes a start motor step 847. In step 847, microprocessor 518generates the appropriate RESET and ENABLE signals to the motorcontroller 508 so that correct HIGH_ and LOW SIDE CONTROL signals areasserted to cause the initial movement of the motor 52. The time periodsfor which these signals are asserted are based on the data retrievedfrom field 442 of NOVRAM 74. The current drawn by motor 52 during theinitial phase of its operation is monitored based on the current leveldata contained in fields 402 and 403 of the NOVRAM 74.

[0265] Also as part of the start motor step 847, microprocessor 518asserts the MOTOR_POWER_ON signal, the MTR_ON/OFF signal and places theFORWARD\REVERSE signal in the appropriate state. Microprocessor 518 alsoasserts the appropriate HPx_ON signal to close the correct relays 746 or748 internal to motor driver and current sense circuit 510. Only withthe closing of relays 746 or 748 will connections to the control consolesocket be made that will allow energization signals to be applied to thecontacts internal to the associated socket.

[0266] After start motor step 847, microprocessor 518 turns on the speedand current set interrupts as represented by step 848. These interruptscause main module 782 to selectively call speed set module and currentset module 788 and 790, respectively, for execution. During the periodof time the handpiece 32 or 33 is actuated, the instructions within thespeed set module 788, the current set module 790 along with those in arun time module, not illustrated, integral with the main module 782 areexecuted by microprocessor 518. Once the interrupts are set,microprocessor 518 generates the signals to the other components ofcontrol console 36 to cause the appropriate energization signals to beprovided to the active, actuated handpiece 32 or 33.

[0267] Once the motor 52 has been initially actuated, a primary signalgenerated by microprocessor 518 is the SPEED_SET_POINT signal since thisis the signal used by motor controller 508 to regulate motor speed. Theinstructions for establishing the SPEED_SET_POINT signal are containedwithin speed set module 788. FIG. 28 illustrates the process stepsperformed by microprocessor 518 based on the instructions containedwithin this module. The initial step performed by microprocessor 518 isa read raw speed signal step 856. In step 856, microprocessor 518 readsthe basic analog signal representative of the user-selected speed forthe handpiece. This signal may be the HP_DVC_x signal from the sensor 94in the handpiece that monitors the position of lever arm 186.Alternatively this signal may be either the FS_FWD or FS_RVS switch ifthe surgeon depressed either foot switches 44 a or 44 b.

[0268] Once the raw speed signal is read, in step 858, microprocessor518 produces a corrected speed signal. The corrected speed signal iscalculated using an established correction function wherein thecoefficients of the function are retrieved from the memory associatedwith the source of the speed signal. Thus, if sensor 94 is the source ofthe raw sensor signal, the coefficients in fields 372-376 of thehandpiece NOVRAM 72 are used as the coefficients of the correctionfunction. If either the FS_FWD or FS_RVS signals are used as the rawspeed signal, coefficients retrieved from foot switch assembly memory392 are used in the correction function.

[0269] The corrected speed signal is then used as a variable in atransfer function to produce an adjusted speed signal as represented bystep 860. This second compensation of the speed signal is performed inorder to minimize any system error so that the resultant SPEED_SET_POINTsignal accurately indicates the surgeon desired speed for the handpiece.The relationship established by the transfer function is that when thecorrected speed signal indicates that the motor should be operating atthe highest possible speed, (either the surgeon set maximum speed or thedefault maximum speed), then the motor should actually be running atthat speed. In one version of the invention, this transfer function is afirst order function. Initially the coefficient of this function isunity. As described hereinafter, as long as the handpiece remainsactuated, the microprocessor 518 will continually adjust the coefficientof this function.

[0270] As part of adjustment step 860, microprocessor 860 may furtheradjust the SPEED_SET_POINT signal to prevent the handpiece motor 52 fromaccelerating/deaccelerating at a rate greater than that specified by thedefault (NOVRAM) or use-set acceleration/deceleration rate. In order toperform this step it may be necessary for the microprocessor 518 tocompare the user speed to the actual speed of the motor based on thefiltered TACHOMETER signal.

[0271] The adjusted speed signal produced as a result of the applicationof the corrected speed signal to the transfer function is then outputtedby microprocessor 518 as the SPEED_SET_POINT signal. Motor controller508 then controls the assertion of the HIGH_ and LOW_SIDE_CONTROLsignals based in part on the amplitude of this signal.

[0272] Microprocessor 518 then determines if the SPEED_SET_POINT signalindicates that the motor is to be operated below the minimum, stall,speed as specified from the data retrieved field 388 of NOVRAM 72,represented by step 862. If this comparison indicates that the motor isto be operated above the stall speed, execution of speed set module 788is terminated as represented by exit step 864.

[0273] If, however, the comparison of step 860 indicates that the motoris to be run below the stall speed, microprocessor 518 turns off thespeed set and current set interrupts in a step 866. Integral with thisstep is the zeroing of the SPEED_SET_POINT signal. Microprocessor 518then asserts an appropriate set of BRAKE signals to motor controller 508as represented by step 866. Motor controller 508, based on the assertionof the BRAKE signals, causes HIGH_and LOW_SIDE_CONTROL signals to beactuated that result in the ordered stopping of motor 52. The rate atwhich microprocessor 518 asserts the BRAKE signals is based on the dataretrieved from the brake control field 444 of NOVRAM 72.

[0274] Once the brake signals are asserted, microprocessor 518terminates execution of the instructions within the speed set module 788as represented by the transition to exit step 864. At this time, thecontrol console leaves the run time mode and returns to the user timemode as represented by step 889 on the flow chart of FIG. 23. The nextprocess step microprocessor then performs is the motor switch ondetermination step 844.

[0275] The above described speed set module 788 is constructed so thatSPEED_SET_POINT signal is recalculated and asserted before adetermination is made regarding whether or not the user-entered commandindicates that the handpiece is to be operated above the minimum stallspeed. An advantage of this arrangement is that it ensures promptgeneration of a SPEED_SET_POINT signal that accurately represents theuser-entered speed command. If the subsequent determination reveals thatthe user actually has deactuated the handpiece, the relatively shortassertion of the low SPEED_SET_POINT signal will not adversely affectthe subsequent braking of the handpiece.

[0276] The process steps performed by microprocessor 518 based on theexecution of current set module are now described by reference to FIG.29. Initially, microprocessor 518 engages in a read step 872. In readstep 872 microprocessor 518 obtains the adjusted speed signal, thesurgeon-set or default maximum speed signal, the motor speed and thecurrent drawn by the motor.

[0277] It should be understood that this motor speed, as all other motorspeed calculations performed by microprocessor 518 is based on thereceived tachometer signal as filtered by the coefficient contained intachometer filter field 448 of the handpiece NOVRAM 72. Similarly, thisand all other current drawn readings are based on the AVERAGE_I from themotor driver and current sense circuit 508 as filtered by thecoefficient contained in current filter field 446.

[0278] Once the requisite data is read, microprocessor executes a step874 to determine if the coefficient of the transfer function used toproduce the adjusted speed signal should itself be adjusted. In step874, a first determination is made regarding whether or not the adjustedspeed signal indicates the user has indicated that the motor is to beoperated at its highest speed. If the user has made such a command, thecurrent drawn by the motor is compared to current limit in the maximummotor current field 404 of NOVRAM 72. If the drawn current is less thanthe designated maximum current, microprocessor 518 proceeds to an updatetransfer function coefficient step 876. If either of these twodeterminations are negative, step 876 is not executed.

[0279] In transfer function coefficient update step 876, the coefficientof the transfer function used to produce the adjusted speed signal instep 860 is updated. More particularly, the coefficient is revised toproduce an adjusted speed signal that, assuming the corrected speedsignal indicates that the motor is to be run at the maximum speed, willcause the motor to run at the maximum speed. This continual adjustmentof the transfer function coefficient serves to minimize variations inthe control of the handpiece owing to the individual variations of thecontrol console 36. Since this updating occurs continually it alsocompensates for changes in component characteristics within the controlconsole 36 that occur as result of thermal changes in the controlconsole. A more detailed explanation of how this coefficient is updatedis found in U.S. Pat. No. 5,543,695, which is incorporated herein byreference.

[0280] After step 876, a set PEAK_I_SET_POINT and GAIN signals step 878is executed. In step 878, microprocessor initially determines the peakcurrent that the motor 52 should draw based on its current speed ofoperation. This determination is made by first determining the maximumtorque the motor should be drawing based on its speed. This maximumtorque is determined by reference to the data table containing therepresentation of the speed/torque plot 438 of FIG. 14. Once the maximumtorque is determined, the equivalent maximum current is calculated basedon a quadratic equation. The coefficients for this coefficient are thosecontained with torque-to-current fields 406-410 within the handpieceNOVRAM 72.

[0281] Microprocessor 518 then establishes the PEAK_I_SET_POINT and GAINsignals based on the calculated maximum current. If the motor isoperating at a relatively high speed such that it should only be drawingrelatively small current, microprocessor 518 will generate a relativelylow PEAK_I_SET_POINT signal. The complementary GAIN signal will be onethat will cause programmable amplifier 756 to significantly amplify thebasic current measurement made across resistor 754. In contrast, if themotor is in a state where it is able to develop a relatively largetorque, draw a significant current, microprocessor 518 will set thePEAK_I_SET_POINT signal relatively high. The complementary GAIN signalis set so that there will be little, if any amplification of the basiccurrent signal.

[0282] Microprocessor 518 then proceeds to execute step 879 in order toset the TIME_OFF signal. This step is performed by reference to the datatables containing the representation of speed/time out plot 808 of FIG.25. Based on reference to the present speed of the motor and byreference to this data table, microprocessor determines the appropriatetime out period for the motor 52 in the event the motor draws a currentin excess of that specified by the PEAK_I_SET_POINT signal. A TIME_OUTsignal representative of this period is then forwarded to motorcontroller 508.

[0283] Microprocessor then executes a step 880 to establish the state ofthe RESISTOR_COMPENSATION signal. As discussed with respect to motorcontroller 508, resistor 721 is selectively connected to the externalimpedance network of the speed feedback control loop. The tying ofresistor 721 to this network is a function of the speed of the handpiecemotor 52.

[0284] In one preferred version of this invention, resistor compensationfield 450 of handpiece NOVRAM 72 includes two speed settings for thecomplementary handpiece regarding when resistor 721 should beconnected/disconnected to the associated external impedance network. Afirst one of the speed settings indicates when the resistor should beconnected/disconnected as the motor speed is increasing. A second one ofthe speed settings indicates when the resistor should beconnected/disconnected as the motor speed is decreasing. These separatespeed settings are typically not identical. In step 880 microprocessor518 reviews the current speed of the motor, its past speed and the speedsettings contained in field 450. Based on this information,microprocessor 518 asserts and negates the RESISTOR_COMPENSATION as isappropriate. Thus, microprocessor 518, in real time, adjusts theexternal impedance of the speed loop compensation allowing optimal speedloop stability of multiple speeds. This serves to enhance the range ofspeeds over which control console 36 can hold the speed control stable.

[0285] The execution of resistor compensation step 880 completes theexecution of the instructions contained within current set module 790.Microprocessor then leaves this module as represented by the transitionto exit step 882.

[0286] When the system 30 is in the run time mode, the run time moduleof main module 782 is also executed. This sub-module is represented bytwo steps, steps 886 and 888 depicted on the flow chart of FIG. 23. Step886 is a run time update system step. In step 886 microprocessor 518monitors signals representative of state conditions most critical to theoperation of the system 30. These signals include: the TACHOMETER signalrepresentative of motor speed; the AVERAGE_I signal; the 40 VDC signal;the HP_CUR signal representative of the bias current drawn by thedevices internal to the actuated handpiece; any signal indicatingadjustments have been made to the user-setable motor maximum speed, andthe DISPLAY_TEMP signal indicating the temperature of display 37. Alsoduring the update system step 886 microprocessor 518 monitors thesignals of the devices internal to the actuated handpiece if thesesignals are not used to establish speed control. For example, if one ofthe devices is the described temperature sensor 96, the complementary HPDVC x signal is monitored during the execution of step 886.

[0287] Also during step 886, microprocessor 518 responds to themonitored signals as appropriate. For example, if the surgeon hasadjusted the maximum speed for the handpiece, the internal maximum speedsetting for the main controller 492 are made. If the DISPLAY_TEMP signalindicates a change in display temperature, the appropriate adjustmentsare made to the CONTRAST and BRIGHTNESS signals in order to maintain aconstant image on display 37. If the bias current is outside the rangespecified by fields 398 and 400, microprocessor 518 recognizes thehandpiece 32 as being in the fault state. If this determination is made,microprocessor 518, as when the handpiece is in the other fault states,then inhibits the continued actuation of the handpiece 32.

[0288] Following step 886, microprocessor performs a run time updateuser step 888. Initially, it should be recognized that as soon as thesystem 30 transitions from the user time mode to the run time mode,display input/output controller 512 is instructed to switch frompresenting the user time image of 812 of FIG. 26 to a run time image 890now described with respect to FIG. 30. Run time image 890 contains onlythe information surgeon personnel consider significant when a handpieceis actuated. In the depicted version of image 890, this information issimply the actual speed of the handpiece and the buttons required toadjust the maximum motor speed of the handpiece. As can be seen byreference to FIG. 30, image 890 has a speed presentation 892 that islarger than the maximum speed presentation 840 presented on the usertime image 812 and that occupies substantially the width of the screen.The increase in size of the speed presentation and the elimination ofsubstantially all other images from display 37 minimizes the amount ofeffort required to read the run time speed of the handpiece.

[0289] During execution of the majority of the run time user updatesteps 888, the primary task of microprocessor 518 is to forward theappropriate command to the display input/output controller to cause themotor speed to be presented in real time. If other signals monitored bymicroprocessor 518 indicate other component state changes about whichthe user should be notified, other appropriate commands are sent to thedisplay input/output controller 512. For example, if a HP_DVC_x signalindicates that a handpiece is excessively warming up, microprocessor 518will instruct display input/output controller 512 to both present anappropriate warning image and generate an appropriate audio warningtone.

[0290] The processing steps performed by microprocessor 518 duringreturn to user time mode step 889 will now be discussed in more detail.As part of step 889, microprocessor 518 accesses EEPROM communicatormodule 786 to write into the handpiece EEPROM 74 data reflecting the newuse history of the handpiece. Microprocessor 518 also instructs displayinput/output controller 512 to stop producing run time image 890 andreturn to producing user time image 812.

[0291] Once system 30 of this invention enters the run time mode, theexecution of the run time module steps 886 and 888 are the primaryprocessing steps executed. The execution of the instructions containedwithin the speed set and current set modules 788 and 790, respectively,occur as the interrupt executions. It is however, most important thatthe SPEED_SET_POINT signal be updated as frequently as possible.Accordingly, in preferred version of the invention, the interrupts areset so that the instructions within speed set module 788 are called forexecution every 5 msec. The remaining motor control signals, thePEAK_I_SET_POINT, the GAIN, the TIME_OFF and the RES_COMP signals do notneed to be updated as frequently. Accordingly, the interrupts are set sothat the instructions within the current set point module 790 are calledfor execution approximately every 50 msec. Steps 886 and 888 of the runtime module do not have to be executed as frequently, these steps areonly called for execution once every 150 to 500 msec. In some preferredversions of the invention steps 886 and 888 are executed approximatelyonce every 200 msec.

[0292] In order to ensure that the above processing can all take place,in a preferred version of the invention it takes approximately 2 msec toexecute the instructions contained in speed set module 788,approximately 15 msec to execute the instructions contained in currentset module 790 and approximately 60 msec to execute steps 886 and 888 ofmain module. Collectively, this ensures that once every 200 msec, theSPEED_SET_POINT signal is updated 40 times, the remaining motor controlsignals are updated four times and the remaining system control signalsare updated once. This rapid updating of the SPEED_SET_POINT signalassures that the changes in the signal presented to motor controller 508appear essentially analog.

[0293] As discussed above, one option system 30 allows surgicalpersonnel is to retain an indication of the system settings preferred byindividual surgeons for specific medical procedures. This information isstored in display input/output controller EEPROM 662 and is selectivelyretrieved while the system is in the user time mode. FIG. 31 illustratesa surgeon selector image 896 that is presented on the display 37 basedon the depression of options button 838 and other appropriate buttons,not illustrated.

[0294] Surgeon selector image 896 includes scroll lines 898 thatidentify both a specific surgeon and a specific surgical procedure.Buttons 900 to the right of scroll lines 898 are manipulated to presenta list of surgeons/surgical procedures stored in the system. A doctorselect button 902 to the left of scroll lines 898 is depressed to enterthe surgeon preferences for the indicated surgeon/procedure. Oncesurgeon select button 902 is depressed, microprocessor 518, throughdisplay processor 654, retrieves from EEPROM 662 the selected storedsettings.

[0295] If settings for a new surgeon/procedure are to be entered, a newsurgeon 904 button is depressed. The depression of new surgeon buttoncauses a keyboard to be presented on display 37 so that identifying dataabout the surgeon/procedure can be entered. Then, at the end of theprocedure the settings established by the doctor are stored. Thesesettings may be initially stored as part of the return to user time step889. Button 906 is depressed to erase the record for a particularsurgeon/procedure. Button 908 is depressed if there is a need to editthe surgeon/procedure identifier.

[0296] Normally, for each surgeon with a stored procedure, after theprocedure is again performed, the new settings entered by the doctor arestored. The depression of lock procedure button 910 stops this systemfrom engaging in this automatic rewriting of the stored settings.

[0297] The direct drive controller 792 includes the softwareinstructions microprocessor 518 requires to supply energization signalsto a handpiece operated in the direct drive mode as opposed to the abovedescribed motor drive mode. When these instructions are executed, thecommutation cycle of FETs 730 and duty cycle of FETs 732 are controlleddirectly by microprocessor, independent of any back EMF pulses receivedas Wx signals. Consequently, it is possible to include in the handpiecea transformer for converting the high voltage (40 VDC) low current (10Amp) signal produced by the control console into a lower voltage (10VDC) high current (40 Amp) signal used by some surgical tools. Suchconversion is possible by including in direct drive controller module792 instructions for appropriately regulating the chop and duty cyclesestablished by motor controller 508. The instructions in module 792would be executed based on appropriate instructional commands stored inNOVRAM 72 for the complementary handpiece.

[0298] Thus, when a handpiece is connected to the complementary controlconsole 36 of system 30 of this invention, main processor initiallyreads the data stored in the handpiece NOVRAM 72 to determine if thehandpiece is to be driven in the motor drive mode wherein the drivesignals generated based on the state of feedback signals supplied fromthe motor, the back EMF signals, or in the direct drive mode.

[0299] If the handpiece is driven in the motor drive mode, maincontroller 492 generates the requisite SPEED_SET_POINT,PEAK_I_SET_POINT, GAIN, RES_COMP and TIME_OUT signals the complementarysub assemblies require in order to ensure the proper energizationsignals are applied to the windings of the motor internal to thehandpiece. As long as the motor is developing less than its maximumtorque for its given speed, motor controller 508 and motor driver andcurrent sense circuit 510 will assert the correct signals to tie thewindings of the motor to the +40 VDC rail 498 and ground. The actualtiming of these connections, is further regulated by when the back EMFsignals from the motor are received. Proper speed feedback control ismaintained by the RESISTOR-COMPENSATION signal regulating the impedanceof the external impedance network connected to the speed feedbackcontrol loop.

[0300] Comparator 692 continually compares the selectively amplifiedISENSE signal to the PEAK_I_SET_POINT signal to determine if the torquedeveloped by the motor exceeds its established maximum. If thiscondition occurs, the output signal from comparator 692 changes state.Motor control chip 686 interprets the change in the state of thecomparator signal as a command to negate the assertion ofLOW_SIDE_CONTROL signals. The period of time in which the assertion ofthese signals is to be negated is a function of the TIME_OUT signal.

[0301] Control console 36 also monitors the internal temperature of theactuated handpiece. If this temperature exceeds a selected level, anappropriate warning message, and/or override request will be presentedon display 37. The surgical tool system 30 of this invention isconfigured so that the information regarding the operating parameters ofeach handpiece is stored within memories 72 and 74 internal to thehandpiece. When the system is initialized, the control console 36 readsthis data and configures itself to supply the appropriate energizationsignals to the handpiece. Thus, the system 30 of this invention makes itpossible to provide a single control console 36 that can be used toprovide energization signals to handpieces with motors that rotate atspeeds as low as 10 RPM to speeds as high as 100,000 RPM and that havepower requirements that range from as low as 20 Watts to as high as 500Watts. (This upper limit assumes an appropriate power supply module 494is attached.) The ability to provide a single control console that canbe used to energize such a wide range of instruments eliminates the costand surgical suite clutter required with having to provide the multipleconsoles.

[0302] The control console 36 is also configured to not only supply theenergization signals required to actuate a motor internal to ahandpiece, it can supply direct drive energization signals to ahandpiece. This further increases the number and kind of handpieces thatcan be incorporated into this system 30 so as to further reduce thenumber of additional control consoles that need to be provided.

[0303] Moreover, the control console 36, by reading the memories 72 and74 internal to the handpiece, automatically establishes limits regardingthe maximum speed at which the handpiece motor should be driven and thecurrent that can be drawn by the handpiece. This eliminates thepossibility that, as a result of human error, the control console 36could be configured so as to result in the application of energizationsignals that cause the motor to be overdriven or that would allow thehandpiece to draw excessive current. Both of these situations couldpotentially cause inadvertent injury to the patient or the hands of thesurgeon working with the handpiece.

[0304] Still another feature of the system of this invention is that itallows each handpiece to be readily combined with accessory units. Ahandpiece can, for example be easily fitted with a hand switch 39 and/ora light-and-water clip 45. Both these accessories are completelyremovable from the handpiece; the handpiece does not have any mountingtabs for facilitating accessory attachment. Thus, a single handpiece canbe used both by personnel that prefer using a smooth, cylindrical tooland by personnel who prefer working with the accessory attachments. Thisfeature of the invention serves to eliminate the need to providedifferent handpieces to accommodate the personal preferences of thesurgeons working with the handpiece. This elimination in the need toprovide handpieces with different accessories permanently attachedthereto further serves to reduce the cost of outfitting a surgicalsuite.

[0305] Furthermore, the removable hand switch 39 of this invention isdesigned so that slip ring 184 prevents the switch from being fittedover the rear of a handpiece 32 when a cable 43 is coupled thereto. Tab196 integral with slip ring 184 is dimensioned to prevent the handswitch 39 from being slipped over the forward end of the handpiece 32.These features of the invention thus prevent the hand switch 39 frombeing fitted to a handpiece while a cable 43 is attached thereto. Thecable 43 must be disconnected from the handpiece 32. Thus, if during theprocess of attaching the hand switch 39, magnet 190 inadvertently comeswithin close proximity to Hall effect sensor 94, since the handpiece 32is disconnected from the control console 36, accidental actuation of thehandpiece is prevented. In order for the system 30 to operate, the cable43 must be properly coupled to the handpiece. In order for cable 43 tobe so coupled, tab 196 must be seated in complementary slot 185. Thesefeatures ensure that the hand switch 39 will not fall out of alignmentwith the handpiece 32 once the system is properly configured.

[0306] Moreover, in this invention, the data regarding thecharacteristics of the output signals asserted by the on/off/speed Halleffect sensors in each handpiece is stored within the handpiece. Thismakes it possible to use each handpiece with different removable handswitches 39 since the control console 36 can make the necessary signalprocessing adjustments to adjust for deviations in the magnetic flux ofthe hand switch magnets 190.

[0307] Similarly, the installation of the memory 329 in the foot switchassembly 46 allows the foot switch assemblies and control consoles 36 tolikewise be interchanged.

[0308] Still another feature of this invention is that the handpiecescan be provided with internal temperature sensors and the NOVRAMs 72internal to the handpieces contain data regarding the acceptableoperating temperatures for the handpieces. This makes it possible toconfigure the system so that in the event the operating temperature forany of the handpieces exceeds the normal temperature for that specifichandpiece, the console will provide a warning statement, reduce thepower applied to the handpiece and/or deactivate the handpiece if itbecomes excessively warm. This feature of the invention ensures that, ifdue to use or malfunction, a handpiece becomes excessively heated, therewill be little possibility that it will burn the hands of the personholding it. Moreover, as described with respect to handpiece 32, it ispossible to provide handpieces of this invention so that there is arelatively short thermally conductive path between temperature sensor 96and the windings 58 and front bearing assembly 64. For example, in someversions of the invention temperature sensor 96 is less than 100 milsfor windings 58 and more preferably only approximately 20 to 50 milsfrom the windings. Temperature sensor 96 is likewise less than 500 milsfrom front bearing assembly 64 and more preferably less than 300 to 400mils from the bearing assembly. In the event the handpiece 32 is droppedthis front bearing assembly 64 may go out of alignment even though suchfailure is not readily detectable by the operation of the handpiece. Asa consequence of this or other failures, windings 58 may rapidly heat.When this bearing/assembly is so out of align, the actuation of thehandpiece will, however, result in the significant generation of heat bythe windings 58 and/or bearing assembly 64. Owing to the relativelyclose placement of the temperature sensor 96 to the windings 58 andbearing assembly 64 the sensor will provide a prompt indication tothrough the control console display 37 that the handpiece isoverheating. This will give the personnel using the handpiece someindication of the malfunction before excessive, injury or componentfailure inducing heat is generated.

[0309] The EEPROM 74 internal to the handpiece provides an indication ofthe total time the handpiece has been actuated. Having the ability toeasily obtain this information makes it easy for personnel charged withthe maintenance of the handpiece to determine if the handpiece needs tobe subjected to a maintenance inspection. The information in EEPROM 74can also be used by the manufacturer of the handpiece as the basis fordetermining if a particular handpiece is still under warranty.

[0310] The ability of the EEPROM 74 to store data regarding the maximuminternal temperature of the handpiece, the highest current drawn by thehandpiece and the total power consumed by the handpiece is also usefulto persons charged with the maintenance of the handpiece for determiningwhether or not the handpiece is functioning normally.

[0311] The control console 36 of the system 30 of the invention doesmore than just regulate the operation of handpieces having differentenergization signal requirements. The control console is furtherconfigured to provide integrated control of the accessories, anirrigation pump 40 and an illuminating bulb 248 that are often used inconjunction with a surgical tool. This integrated control eliminates theneed to provide an additional controller in the surgical suite.

[0312] Still another feature of the control console 36 of this inventionis that it has three safety switches to prevent power fromunintentionally being applied to a handpiece. For the MOTOR_POWERenergization signals to be applied from the AC-to-DC converter 494 to ahandpiece port, first the MOTOR_POWER_ON signal must be asserted bymicroprocessor 518. Then, the MOTOR_ON signal must be asserted by themicroprocessor 518 to avoid the default negation of theHIGH_SIDE_CONTROL signals by OR gates 698. Finally, even if the FETs 728are switched on, the MOTOR_POWER signals will only be applied to ahandpiece socket if the associated relays 746 or 748 are closed by theassertion of the requisite HPX_ON signal. This redundancy substantiallyeliminates the possibility that the control console 36 willinadvertently apply the MOTOR_POWER energization signals to a handpiece.

[0313] Still another feature of this invention is that the inductors 740substantially reduce the magnitude of the current drawn by the FETs 732as a result of the state transition of FETs 730 and 732. The reductionof this current draw eliminates the need to provide filters in thecurrent sense portion of the motor driver and current sense circuit 510or software filters in the main controller 492 to compensate for theapparent excessive current draw that would other wise be measured by thecurrent sense circuit.

[0314] The control console 36 of the system 30 of this invention isfurther configured so that the post-excess current drawn time-out periodduring which the assertion of energization signals to the handpiece isnegated is set as part of the process of configuring the control consolefor use with a handpiece. The ability of the motor controller 508 tomake this adjustment further enhances the ability to use the controlconsole 36 with handpieces that have different power operatingrequirements.

[0315] Still another feature of this invention is that control console36 allows a surgeon to rapidly alternate between using a first handpieceand a second handpiece. This facilitates the rapid as possiblecompletion of the surgical procedure. By being able to perform thesurgical procedure as quickly as possible, the amount of time thesurgical site is open to infection and the patient must be keptanesthetized is likewise lessened. System 30 of this invention alsomakes it possible for the surgeon to set the rates at which thehandpiece motor 52 accelerates or decelerates.

[0316] It should be recognized that the foregoing description isdirected to a specific embodiment of this invention. It will beapparent, however, from the description of the invention that it can bepracticed using alternative components other than what has beenspecifically described. For example, it is clearly not always necessaryto provide a handpiece with EEPROM for storing data about events thatoccur during the operating life of the handpiece. Similarly, it may notalways be necessary to provide the non-volatile memory internal to thehandpiece with all the data provided in the described version of theinvention. For example, in some versions of the invention it may benecessary to provide only a minimal amount of data regarding the maximumspeed at which the handpiece motor can operate and the maximum currentthe motor should draw. Alternatively, in some versions of the inventionit may be desirable to provide the handpiece memory with data differentfrom what has been described.

[0317] For example, as illustrated by FIG. 32, handpiece NOVRAM 72 maybe provided with a set of accessory head fields 920. These fields 920are provided in a handpiece to which it is necessary to attach acomplimentary accessory head. This accessory head contains gears and atransmission mechanism necessary for transferring the motive powerproduced by the motor internal to the handpiece into a form in which itcan be used by a cutting accessory attached to the accessory head.Typically these gears reduce the rotational rate of the motor forapplication to the cutting attachment.

[0318] As represented by the first accessory head field 920, each ofthese fields is composed of a number of sub-fields. The first sub-fieldis an accessory head name field 922 that identifies the specificaccessory head. The second field is a ratio field 924. Ratio field 924,like gear ratio field 398 indicates the gear ratio for the particularaccessory head. A maximum speed field 925 contains information regardingthe maximum speed at which the tip of the accessory head can be driven.An increment field 926 contains an indication of the rate at which theuser-set maximum speed of the accessory head can be driven. There isalso a current limit field 928. Current limit field 928 contains dataindicating a correlation between the maximum current the handpiece candraw and the maximum current the accessory head can draw. Typicallyfield 928 contains an indication of the percent of the maximum torquethe handpiece can develop, (the current the handpiece can draw). Thereis also a current shut-off field 930. Current shut-off field 930contains an indication of the maximum current the handpiece with theparticular accessory head attached can draw. If the AVERAGE_I signalindicates the current drawn by the handpiece exceeds the amountspecified in current shut-off field 930, microprocessor 518, preventsthe further application of energization signals to the handpiece, insome cases by requiring a cold start of the handpiece.

[0319] In this version of the invention, during the initial systemdefinition step 804, microprocessor 518 reads the handpiece NOVRAM 72 todetermine if it contains any accessory head fields 922. If these fieldsare absent, microprocessor 518 proceeds to initialize the system 30 asdescribed. If accessory head fields 922 are present, microprocessor 518instructs display input/output controller 512 to present the retrievednames from the individual accessory head name fields 922 on the initialuser time image 812. These names are presented below tool identificationline 839 as actuatable buttons. The surgeon using the system is thenrequired to press then appropriate name button to identify the accessoryhead that is attached to the handpiece. Main controller 492 thenregulates the application of energization signals to the handpiece basedon the remaining data contained in the accessory head sub-fields 924-930for the selected accessory head.

[0320] System 30 may further be configured to provide different,user-selectable control options. For example it may be desirable toconfigure the system so that the user can first establish a fixed speedfor the handpiece. Then, the depression of either the hand switch orfoot pedal will cause the motor to operate only at the established,fixed speed. Alternatively, it may be desirable to give the option ofallowing surgical personnel to reset the hand switch or foot switchcontrolling the motor from functioning as contact switches that requireconstant depression in order for the motor to be actuated to single pullswitches that can be pressed once to turn the motor on and a second timeto turn the motor off.

[0321] It should similarly be recognized that the devices installed in ahandpiece may be different than what have been described. For example,if a particular handpiece is a cauterizing tool, it may be desirable toprovide a remote sensor internal to the handpiece that can measure thetemperature of the surgical site to which the tool is applied.Similarly, this tool may also be provided with a second temperaturesensor that monitors the internal temperature of the tool. In a similarcontext, it should also be recognized that other handpieces may beprovided with none, one, three or more devices each of which assert asignal that is monitored by the control console.

[0322] Also, while one specific construction was described, otherhandpieces could have different structures without departing from thenature of this invention. It may, be desirable to provide two circuitplanes inside the handpiece. A first one of the circuit planes couldprovide the conductive paths to the devices and power consuming membersinside the handpiece while the second plane could provide the conductivepaths to a removable memory module.

[0323] In the described version of the invention the motors 52 internalto the handpieces were described as three-winding brushless, Halless DCmotors. It should be recognized that in other versions of the inventionhandpieces with different motors may be provided. In these versions ofthe invention, the motor control and motor drive portions of the controlconsole 36 would be appropriately reconfigured to provide the necessaryenergization signals to the handpieces. Alternatively, it may bedesirable to provide a control console 36 with different motorcontrollers and motor drivers so that it can be used to provide thedifferent types of energization signals required by differenthandpieces. Similarly, it is contemplated that different power convertermodules 494 can be provided to facilitate the use of the surgical toolsystem 30 of this invention with line voltages of different countries.

[0324] As discussed above with regard to the ability of the controlconsole 36 to provide direct drive energization signals, it shouldfurther be recognized that not all handpieces may have direct drivenmotors internal therewith. The system may be configured so that thecontrol console substitutes as battery pack for a handpiece.Alternatively a handpiece may be some type of device such as a laser orultrasonic generator or sensor that does not have an internal motor.

[0325] It should also be recognized that the control console 36 may havea different configuration than what has been described. For example,some versions of the invention may have parallel or multiplemicroprocessors that perform the functions of both the main controller492 and the motor controller 508. Similarly, it may not be necessary toprovide the processor internal to the control console 36 with thesoftware tools employed in the described version of the invention.Furthermore, while one particular timing sequence for executing softwaretools during the actuation of a handpiece was disclosed, in otherversions of the invention tool execution may occur at a different rate.For example, it may in some versions of the invention be necessary toexecute the software tool that determines if a desired current is beingdrawn more often than other software tools. Also, the algorithmsemployed may vary from what has been described.

[0326] Moreover, while in the described version of the invention, thecontrol console is described as having a power supply 494 for convertingline voltage into voltages useful for energizing components internal tothe control console and useful for application to the complimentaryhandpiece, this module may not always be required. It may be possible toprovide the control console with a battery pack capable of supplying thepower required for energization of the control components and thehandpiece. In these versions of the invention, in order to reducecontrol console size and internal console power draw, the touch screendisplay and other components such as the pump may be eliminated.

[0327] It should also be recognized that the control console 36 can beprovided with additional components and/or process instructions so that,in addition to be used with handpieces 32 or 33 provided with NOVRAMs 72containing data regarding their operating characteristics, it can alsobe used with handpieces without such memories. To provide such controlit may be necessary to provide one or more additional sockets 505(FIG. 1) on the face of the console 36 to provide for the cables usedwith these handpieces. In such a system, main controller 492 is furtherprovided with an additional software module that contains theinstructions for providing energization signals to this handpiece.Button 817 presented with user time image 812 (FIG. 26) illustrates oneway of selecting this handpiece to be the active handpiece.

[0328] It should likewise be understood that the disclosed process stepsperformed by main controller 492 represent only a single set of suchsteps that can be performed in one version of this invention. Forexample, in the described version of the invention, main controller 492has been described as basically reading the available data and thenasserting or adjusting the associated output signals. This may notalways be required. In some versions of the invention, main processormay read some data and immediately act on it. For example, the systemcould, upon reading the desired pump setting, immediately readjust thecomplementary PUMP_SET_POINT.

[0329] Similarly, the sequence and timing of the processing steps may bedifferent from what has been described. For with the describedhandpieces, the SPEED_SET_POINT signals are that is most frequentlyupdated signals, there may be some systems or some handpieces for whichthat is not always the situation. Thus, for some surgical procedures thespeed of the handpiece may not be the most critical factor but thetorque it develops, the current it draws, may be. For thesesystem/handpieces, the PEAK_I_SET_POINT signal or a CURRENT_SET_POINTsignal may be the signal that is most often reset by the main controller492.

[0330] Moreover, some preferred versions of the invention are furtherconfigured so that if two handpieces, both with hand switches 39attached to control console 36, and one hand switch is depressed, thecontrol console will automatically designate the associated handpiece asthe active, actuated handpiece. If both hand switches 39 are depressed,the first one to send a signal to the console 36 locks out the switchsignal from the other handpiece. In these versions of the inventionmicroprocessor 518 is configured so that when in the user time mode, itcycles the HP_(—)1/2 to periodically pole the HP_DVC_x_x signals thatcould potentially generate the switch signals. The control console 36typically does not present any message to the user on display 37 toindicate that this poling is occurring.

[0331] It should likewise be recognized that the images presented on thedisplay 37 can vary from what has been described. As previouslydiscussed, the handpiece NOVRAM 72 can store data regarding any customimage that needs to be presented during its operation. Alternatively,user time and run time images only slightly different from what has beenillustrated may be presented. For example, for some handpieces it may bedesirable to present a graphical indication of the speed at which thehandpiece is operating. This presentation may also be a matter ofphysician preference. For still other handpieces, it may be desirable oroptional to, in addition to presenting an indication of handpiece speed,further present an indication of the torque developed by the handpiece.For both these options, it is still anticipated that the run time imagespresenting this information will be larger in size than the initialimage presented as the user time image.

[0332] Therefore, it is an object of the appended claims to cover allsuch modifications and variations as come within the true spirit andscope of the invention.

1. A powered surgical tool system, said system including: a poweredhandpiece for application to a body, said handpiece having a powerconsuming unit to which a select energization signals having a definedset of characteristics are applied and a non-volatile memory in whichdata regarding the characteristics of the energization signals that areapplied to said handpiece are stored; a control console configured to beconnected to said handpiece for applying energization signals theretoand for reading data from said memory in said handpiece, said controlconsole having: a drive unit for generating the energization signalsrequired by the handpiece, said drive unit being configured to generatethe energization signals based on at least one drive unit command signalreceived thereby; and a main controller connected to said memory in saidhandpiece and to said drive unit, said main controller being configuredto retrieve the data stored in the memory in the handpiece and togenerate said at least one drive unit command signal to said drive unitso as to control the generation of the energization signals by the driveunit in response to the data retrieved from the memory in the handpieceand an on/off signal; and a manually actuatable switch connected to saidmain control console for generating said on/off signal and applying saidon/off signal to said main controller of said control console. 2-64.(Cancelled).